Even a google search can help you find stuff. I also recommend reading all the stuff on the Bettysplendens site.
There are basically 5 tail types. Veiltail (VT), Crowntail (CT), Halfmoon (HM), Plakat (PK), and Double Tail (DBT). There are also Super Delta(SD) and Delta(DT) which are basically HM that don't have a 180* spread.
There are also mixtures of those tail types such as a Halfmoon Plakat (HMPK) or Crowntail Plakat (HMCT).
As for colors there is almost every color under the sun available to choose from. Pick one you like and that breeds true and base your line on that. But above color you should learn about form and finnage. Learn what goes into a well put together fish and what to look for in breeding stock. Reading the IBC standards is a great place for that.
As for breeders you can try looking to see if there is an IBC affiliated group near you. Go to IBCbettas.org and look under their chapters section. Besides that you can try googling Betta breeders and your area and see what comes up.
Aquabid is an excellent source of fish but you have to know what to look for or you might get sent a bad fish. Many betta groups share fish between one another and will gladly give a new member a pair for free.
There is also the IBC new breeders program where you can request an IBC affliated breeder to send a pair... it may or may not be something you like but its usually free (minus shipping).