There's two Tau fleet lists out there. The Kor'Vatta fleet list (which is the blocky, more civilian-ish one, with client race allies like Kroot, Nicassar and Demiurg), and the Kor'or'Vesh fleet list (which is the Forgeworld, more professional navy-ish one).
All the rules for them (well, all the rules for BFG, period) are available online for free.
EDIT: the FW Kor'or'Vesh list also allows you to mix in Kor'Vatta ships, as long as you don't spend more points on them than on the main. So you can mix and match, and also throw in a Kroot Warsphere or a squadron of Nicassar Dhows.