I was the originator of this post... Since the time I wrote this request, Xanga has provided a WordPress compatible format you can use to import your blog to WordPress.
From your private homepage on Xanga, click on Settings, and then click on Weblog Archives. If you've never updated your archives, then click the button that says "Update your archives." If that's the case, then you'll have to wait until they're ready. Otherwise, if they're already up to date (i.e. - up to the date of your last post), then click on wordpressWXR.zip. The file will download to your computer. After it's on your computer, you'll need to click on it to open it (to get it to the XML format). At that point it's set to import to a blog here on WordPress.
I'm still waiting to see what happens with Xanga, but I have three blogs on Xanga. Regardless of what happens to Xanga, I wasn't planning to keep one of those active there, but I did want to preserve a public record of it. I just imported that one to deerlifexanga.wordpress.com from Xanga, and it worked beautifully. (FYI: the archive did include all the private posts (which remained private) as well as the pulses (which are also marked as private -- even if they were public on Xanga). All the tags carried over. The formatting is off in some places, and eventually I hope to check everything, but I was glad to have the blog copied over here.)
You can find the import instructions here: http://en.support.wordpress.com/import/ -- Just follow the instructions for WordPress.
I've still not downloaded my photos, so that's my next step! ;)
I hope this helps! If you have any questions, please ask.