Actually, I guess I don't know the "proof texts".
hmm... ok
1) II timothy 3:14-17
2) 2nd Peter 1:19-21
3) there are others as well that round out the idea...
As I was saying in my previous post though, I am not convinced that finding a proof-text is really the best way to go about it, even though there aome out there. The scripture is primarily a narrative through which we make inferences about correct belief, it is not primarily a list of axioms upon which we build edifices of deduction.
In relation to the question of sola scriptura, as with an issue like the trinity, I think it is better to try to discern the overall direction scripture is headed instead of looking for a perfect proof-text. When you look at the scriptures you see traditions mentioned, sometimes in a bad light sometimes in a good light. You see the scriptures exalted in many places as the standard of faith. You see Jesus rebuking false traditions. You see the Jews recovering true worship when they recover the law. All this being put together, one sees patterns in the biblical record which point out to us how we should interact. That combined with some of the various proof-texts and historical arguments is how the doctrine of sola scriptura is developed.
One other thing, as IK pointed out, we defend the scriptures as the sole infallible rule of faith, not the sole rule of faith.
I've seen the Timothy thing that's supposed to get me an infallible text, but I can't find anything that says that the Bible is the only source of true information about God... And if there's other sources, then sola scriptura isn't quite right, so far as I can tell.
Unless you are being sloppy in your use of language - in which case I'm just going down a rabbit trail - the issue isn't the existence of true information about God in other places, which is not a problem. The issue is over whether those sources are infallible in either their transmission of past revelation, infallible in their pronouncements about faith and morals or infallible in their reception and pronouncement of new public revelation.
Confessional protestants have never had a problem with fallible rules of faith outside the scripture, we have our primary beef with those who claim infallible authority outside of it.
Anyway, I'd be very interested in knowing what the "proof texts" are, and how they are interpreted to build the case for sola scriptura. I've never seen this done in detail, and I may have missed something.
I'd get the books IK mentioned (at least the first book in the series as it deals with this question). As they are written for lay-people, they aren't too hard to read. At the very least, it'll get you a general overview of the issues at hand. I'd do it myself, but I don't have that much time, nor is biblical exegesis my specialty.