I was originally going to link some good web-casts from Erik Leaseburg.
I then found the BizTalk Rangers super site here:
It basically contains everything you can shake a stick at (if you are of the stick shaking mentality).
Jan 9 JUPBAG-13: Health and Activity Tracking (HAT) & Debugging - Patrick Smith
Feb 27 BizTalk Explorer & Administration - Erik Leaseburg
Apr 2 Performance, Stress & Scalability - Erik Leaseburg
Aug 20 BizTalk Configuration and Administration – Erik Leaseburg
Oct 1 BizTalk PowerToys - Erik Leaseburg
Oct 8 JUPBAG-41: BizTalk 2004 Administration Management Tool - Paul Somers (Charteris)
Oct 15 JUPBAG-42:
Apr 1 BTSBAG-58: Multi-Server BizTalk 2004 Installation and Configuration - Naveen Goli and Paul Davidson
Feb 10 BTSBAG-81: BizTalk Server 2006 Lifecycle: Deployment, Monitoring & Maintenance -
May 19 BTSBAG-90: BizTalk 2004 Operations -