But how do you download version 7.1a, now that TrueCrypt closed their site? Who do you trust? The answer is math! Trust the digital certificate used to sign the installation set, not the site you download it from. The way to do this is listed below.
Step 1 - Find the trusted certificate
Step 2 - Download TrueCrypt 7.1a
Edit: You can also download from this BitTorrent Magnet link. Once again, I checked it to be valid, but you really have to validate yourself.
Edit: Grc.com has a good page explaining the trustwortyness of TrueCrypt 7.1a and offers download links.