From my colleague Bill Ticehurst [MSFT]:

Hi all,

A beta release of Service Pack 2 for BizTalk Server 2004 is now available
from the Connect site.  To obtain this beta perform the following steps:

- Go to http://connect.microsoft.com/
- Sign in with your Passport account  (you need to do this step for it to be
visible)
- Click on Available Connections
- On the second table on the page you should see "BizTalk Server 2004 SP2
beta"

If you download and install this service pack then feedback on any issues or
problems encountered would be greatly appreciated (that's what beta is for
right!).  The email address for feedback is
bts4sp2f@microsoft.com .
Positive feedback will also be of value and is appreciated.

Thanks and regards,

 - Bill Ticehurst [MSFT]