August 2011 Update
Version AJ 5.9 from Anthony Newman is now available and is the most stable yet with support for external monitors (though still some issues to be resolved there). It also runs on Canon 2.0.9 firmware so no need to downgrade now.
The link below now only contains AJ 5.9 and Canon 2.0.9.
Please take note the disclaimers before downloading.
The Unified Version of Magic Lantern has now been ported over to the 5Dmk2 and development of the AJ series has now been discontinued. I am glad to report that the beta version of the Unified 5DMk2 are generally working extremely well and give far better facilities that AJ5.9.
If you wish to avail yourself of this, join the ML-Devel Google Group (groups.google.com/group/ml-devel), make a small donation to the developers, and you will be emailed a link to the firmware. I assure you, it is well worth it. I have been using it on all my shoots since early January.