I just read on Bruce Schneier's blog that SHA-1 has been broken. Bruce states:
SHA-1 has been broken. Not a reduced-round version. Not a simplified version. The real thing.
This attack builds on previous attacks on SHA-0 and SHA-1, and is a major, major cryptanalytic result. It pretty much puts a bullet into SHA-1 as a hash function for digital signatures (although it doesn't affect applications such as HMAC where collisions aren't important).
This is a big deal.