So, you don’t actually need to store player teams – just compare to player properties stored in a databse?
I’d use something like ASP for this (just one of many server-side scripting options).
Capture the form input, pop them into variables, retreive relevant data from DB, do some calcs, fire back a resulkts page to the client. Easy!
Using flash, you’ll get a nicer interface, won’t have page refreshes etc. However, users will need the flash plug-in (fairly ubiqutious these days anyway).
Any additional questions, don’t hesiatte to ask.