This blog was conceived as a repository for announcements that arrive to a number of faculty mailboxes. But by its very nature (serial posts), finding the information you need can be a bit of a challenge.
The fastest way is to let Google be your friend, and use the search window at the top left of your screen to search for keywords within this blog. To further narrow your search, include the relevant year. So, let's say you are interested in biomedical research opportunities for next summer: you could search for "biomedical 2010" and that will retrieve all posts including those two keywords. You can and should try this approach directly via your favorite search engine, adding "undergraduate research" to your search keywords: this will maximize your ability to retrieve possible summer programs that cater to your interests.
Another option is to add this blog to your RSS reader (if that sentence made no sense, try this tutorial). As long as you remember to visit your reader (doh!), you will be alerted when new posts appear in the blogs you track.
And of course, you can become a bona fide groupie and follow this blog (click on the "Follow" link at the top left of this page).