UML/ppc - This is Chris Emerson's page on his port of UML to
PowerPC.
gbootroot
 - A distribution-creation tool with support for creating UML
root filesystems.
BusyBox
- A Swiss Army knife Linux utility which combines a number of
utilities into one binary.  The UML connection is that they use it to
test their stuff and distribute a UML that's been preconfigured for
BusyBox.
User-mode
Linux Community Site - Lots of UML news and tips, along with all 
the up to date patch information.
usermodelinux.co.uk - 
Precompiled kernels and Linux From Scratch filesystems
UML got a 
slashdot 
article on 10/09/2000.
It's also mentioned occasionally on 
Kernel
Traffic, but 
this
story is an especially good one. 
Linux
User magazine ran an article on UML in their November issue.
The article is available 
here as a pdf file.  It's a pretty decent article, although
fairly lightweight technically.  
Dr Dobb's
Journal has a short piece on UML 
here.
Linux Weekly News
ran a nice feature on UML on its 
kernel 
page on 2/15/2001.
The April issue of Linux Magazine with my UML article in it has been printed.  It is now available 
here 
LWN did a nice 
writeup
 of my OLS
talk.
I wrote an 
article for O'Reilly on using UML to simulate disasters and practice
recovering from them.  Linux Today 
picked up on it.  LWN didn't, but redeemed themselves by running an
item I sent them about the 
UML Sysadmin Disaster of the
Month contest.
NewForge ran an article
 about Linux virtual machines which completely failed to
mention UML.  The guy who wrote the article was informed of this and
nicely made amends with this
article, which took the form of an interview.
There's also an 
article on securitywriters.org about using UML as the basis of
a honeynet.