Download this book (PDF) called "Lingua Latina per se illustrata". Is a very good way to learn Latin from zero xd good luck!!
Who do you want to speak Latin with though? Unless you have the money to go to those Latin conventions in the US and Europe (such as Tunberg's conventiculum in Lexington, Kentucky; or the summer program of the Accademia Vivarium Novum in Rome, Italy), which would be quite expensive, you'll probably be talking to people on the Internet.
There are various places on the Internet you could go to in order to practise producing Latin. It will almost always be written Latin, though, so I'm not sure if that's "conversational" enough for you. You could probably arrange to talk with people over Skype or such, but that'll take effort. Some places where people speak Latin are the latind.com forum, and the IRC channels ##latin and ##latinitas on the freenode.net network.
As for resources, there are various books you could read, such as the various old public-domain Dialogi and Colloquia (try searching for "Barlandus' Dialogi" or "Erasmus' Colloquia" or "Mosellanus' Paeodologia" on Google Books). However, you must still get acquainted with Latin for real working through Latin textbooks and reading classical works, paying attention to practise the new words and constructions you learn (most textbooks teach you only to read Latin, not to produce it).
Nullum modum hoc faciendi... ;-)
Lol sorry but I couldn't resist, and yes, my Latin is pretty rusty. I think that Renato is right, textbooks focus on teaching how to read classics rather than writing in Latin yourself - let alone speaking it! We're not even sure how it was suppose to sound (clearly, there's no actual evidence with regard to pronunciation, although recent "reconstructions" are probably accurate).
I'd suggest you to read Juvenal ("Satires") and "Satyricon" by Petronius...They are at a pretty advanced level though (arguably less difficult than Tacitus and some of Cicero's works though), even the best in my class after 5 years of Latin at high school would struggle with it. You'll need a dictionary, a grammar and a lot of patience and individual study! But it is rewarding!
Also I'm gonna need a Latin conversation partner later, so are you up to it?
