Quite abruptly, the TrueCrypt disk encryption tool is no more. The announcement says that the tool is no longer secure and should not be used. The website provides a heavily modified version of TrueCrypt (7.2) that allows one to decrypt the data and export it from a TrueCrypt volume.
Many questions are asked around what actually happened and why, the speculation is rampant. Unfortunately, there does not seem to be any explanation forthcoming from the developers. For the moment, it is best to assume the worst.
My advice would be to not download the latest version, 7.2. Stick to whatever version you are using now if you are using TrueCrypt at all and look for alternatives (although I do not know any other cross-platform portable storage container tools). If you are with 7.1a, the version is still undergoing an independent audit and you may be well advised to wait for the final results.
More on the subject:
Update: there is a Swiss website trucrypt.ch that promises to keep TrueCrypt alive. At the moment, most importantly, they have the full collection of versions of TrueCrypt and all of the source code. There will probably be a fork of TrueCrypt later on.