Here's some Python code for ECB, CBC, DH1080 etc.

[bjrn]

Article:  http://blog.bjrn.se/2009/01/proposal-for-better-irc-encryption.html

Code: http://www.bjrn.se/code/irccrypt/irccrypt.py

Note that the code only does the cryptography, no integration with client software. More info in the article.

Cheers,
Björn

[mouser]

Fantastic article 

I'll add a link to the mircryption page.