I think this year we may go through
www.imagemarket.com - they're pretty quick with their response time, and will work with our logo for no extra charge. We're planning on getting the baseball-style shirts; they'll charge us $10.95 apiece. Once they've received payment, they'll have the shirts delivered in about 12 business days.
On the other hand, if you go to a local shop, one that does shirts for school athletics, they most likely will give you a nice friendly discount, and they've probably got your school logo too.
Good luck! Better to get these ordered sooner than later!