I have a couple of new articles posted at Macworld.com about Time Machine. Both have been generating lots of comments. If you're using Time Machine, or thinking about it, check these out.
Is Time Machine all you need? looks at cases in which Time Machine might be adequate as a sole backup mechanism and cases where you'll want to supplement it with something else - or even skip it altogether. Time Machine tips and troubleshooting covers some of the basics of using Time Machine, including suggestions for files to exclude, ways to restore your data, and more.
Of course (obligatory commercial follows), I go into much more detail about Time Machine in "Take Control of Easy Backups in Leopard," but I squeezed as much useful information as I could into the Macworld articles, and they should make interesting reading even if you've already read either or both of my books on backup.