Any suggestions on how and when I should ask about transferring to a different city?
I have been working at a hotel for about 3 months and would like to put in for a transfer to a different city. I am not sure on the proper way to approach the topic with my manager or the proper time to do so? I think the best time to transfer would be during the hotel's slow period in a couple month.
Thank you in advance for any responses.

In this week's One on one!
As a manager I appreciate this type of news as far in advance as possible. If you've been professional and have achieved results so far, he or she should be more than happy to make your transition easy. If you haven't been professional or achieved results, the same is true.
AND, prepare for some questioning as to why you want to leave so soon. As a manager I'd consider it suspicious to ask for a transfer so soon if you didn't let me know during the hiring process that you planned on leaving quickly.
Tell them as soon as you know where you want to go.
David