In answer to conan79's question:
A lot :) The usuals, Pikachu, Oddish, Doduo, Dudrio, Phanpy etc. After you beat the Pokemon League, a new section opens up where Jhoto Pokemon such as Houndour (sp?), Mareep, Aipom, Ledyba, Miltank, Shuckle, Sunkern, Tediursa, Gligar, Snubbul, Hoothoot...