RSS is a pretty incredible tool, it's like friends list for the entire internet, you might know that your journal has one, just add /data/rss to the end of your livejournal url.
Mine is http://livejamie.livejournal.com/data/r
Now you can take this URL and go to several different places to get updates when I update!
Several places that will send Text Alerts for Free to your Cell (Text Message Rates Apply of Course)
3) Yahoo! Mobile Alerts