Ping-o-Matic works with a bunch of the update services and lists the major ones. You could use http://blog.gs or one of the other ones if you're interested in reading recently updated blogs, or just ping Ping-o-Matic to ping all of the sites at once. The link is: http://pingomatic.com/ .
Someone should dump a bunch of money into weblogs.com or one of these other services to keep them up. They're valuable, and many other services (like my Weblog Bookwatch) depend on them. Without one of these services, the Bookwatch will have to shut down.
Blogger has a changes.xml file, so I'm switching Weblog Bookwatch to that until weblogs.com is back online. If anyone knows of a similar xml file for recently updated TypePad, Movable Type, LiveJournal, Xanga, or WordPress blogs, please let me know.
hmm, not me..."Directory Listing Denied" for the front page and a 404 for changes.xml. My guess is that the server is just overwhelmed and needs new hardware/architecture. (An argument against centralized weblog services?)
The blo.gs cloud has been pretty stable over the past couple of days (though it does seem to be down right now, unfortunately). I wrote a POE component for Perl to automatically get notified of new updates, so it's pretty easy to build a blog-watching tool.
Thanks for the pointer, Ben. Now if I could just get CPAN working properly on my windows box, I'd be set! :) Streaming updates does seem much better, and I should be able to use the blo.gs sample PHP once it's back up and gzipping along.