Universal IM History Decoder decodes message history files of most popular Instant Messengers.

It supports:

MSN Messenger
Yahoo! Messenger
ICQ Messenger
Miranda Messenger
Using this program, you can decode and view not only yours, but also other's conversations, while offline, without password.

For ICQ and Miranda it also recovers stored passwords. All decoded messages could be saved to txt file. Also includes auto-detection of all installed user profiles and date filter selection.