I am very happy in my job, and receiving very good feedback from my supervisor. However, I just got a 2% salary increase, because I was new to the company (so was rated meet expectations).
I am receiving lots of calls from headhunters, and the salary ranges they describe are 10-20% above my current salary. Since I just joined my company less than a year ago, I am happy there, and contributing accordingly, I don't want to leave.
Any suggestions on how to ask for a salary increase in my current job? Don't want to risk my relationship or view perceived as having a lack of commitment.
Thanks!

Point to Accomplishments
You have not given us much data to work from, but I will do my best to guide you toward the right answer, which only you will know, given the paucity of information in your post.
Forget the 10% to 20% you're hearing from head hunters. Those are not real offers. They are enticements so they get another CV to offer to their customers. You must remember that head hunters are salesmen, and you are the product, not the customer. They're just trying to get your CV so they can have a broader range of "product" to offer their customer, the hiring manager.
The first question to ask yourself: How much are you worth to the company? That should be the basis of your pay. What did you do to increase or generate profit at your present company? This does not mean that actual dollars were exchanged for your work. Someone in IT at a manufacturing plant does not directly produce revenue, but his efforts have a definite impact on the work of others that leads to more-direct profit. So, you have to ask yourself, "What did I personally do to increase the profitability of this company?"
From the answer to that question, you then have the leverage to negotiate for more pay. The LAST thing you want to say is, "I have offers of more money elsewhere," because as I stated earlier, you don't have such offers. Your approach should be along the lines of, "I'm grateful that the company values me enough to offer a raise during my first year, but as I probably won't get an opportunity for another raise for at least another year, I'd like to talk to you about the level of my current benefits package." This should be followed with an enumeration of specific things you've done to enhance the functionality of your area. Again, since you didn't state any specifics in your original post, I really don't even have any idea what types of examples I can give. If you're a junior salesman, then you'd probably be pointing at research for quotes or actual sales numbers, but if you're a junior engineer then you're probably going to be pointing to project tasks accomplished.
Basically, you need to point to value that you have added to the process you're involved in that can be attributed directly to your efforts. You should also ensure that you're approaching the decision maker at an appropriate time and in an appropriate manner.
Do more work
In every company I have been at, there is no way to get more pay without doing more work. A good reason to get a pay bump is that you have taken on additional responsibility and are providing additional value.
It's often the case that a new job at a new company will have a higher starting salary but they are probably similar in annual increases. 2% is not really that out of line with what I would expect for a new employee in their first annual review assuming their work was on par but not outstanding.
Companies don't pay you more because you WANT to make more. They pay more because you offer more services.
Don't ask for any more money AND do more work
The "do more work" has already been covered. If you have been there less than 12 months and already got a raise, that is great. What has worked very well for me in the past was to simply keep my head down and outperform everyone around me. My goal is to make it obvious to my boss that a large raise and/or promotion is deserved.
It may make sense for you to change jobs depending on your economic state. It is important to be mindful of the impact on your long term career. Proceed with caution. First, I had a couple of close friends do this when we were fresh out of school. They jumped from job to job and I watched their salaries jump every 6-12 months. When the economy turned down a few of them were very junior to the teams they were on and, as a result, were cut. I know these guys well and I seriously doubt they were the weakest in the group. They simply were not at their companies long enough to establish a strong track record. My career (and salary) growth, by contrast, has been slower but more consistent. I believe part of this is due to my willingness to stick with a company. You can build more internal credibility and become more effective the longer you stay in a place.
Second, the other negative is that when I see candidates with resumes that show multiple tenures of 2 years or less, I rarely call them. I'm willing to bet that other hiring managers do this too. Even if I do call them, if I hear they kept jumping for money, they never make it to the first round of a face to face interview. Frankly, money is rarely a motivator and there will always be another company willing to pay more for a candidate for some other reason.
I encourage you to listen to the series that was just done in Career Tools around picking a company for which to work. They hit on a lot of other concepts. I highlighted the two above because I've seen them first-hand.
-Dan
Wait, and get results first
Wait, get results first, and build the relationships (which takes time).
Companies pay for value received and for expected future value. It's unlikely you've pulled off some major achievement so soon that warrants talking about boosting compensation. (Adding several millions to the valuation of the business would likely qualify, for instance ....)
When review time comes around again, that's a great time to talk out what's up and settle expectations. If you're truly under-compensated, this is when companies tend to even out the inequities.