I had mentioned that I’d quickly developed a helper gem for simplifying using the WorldCat API in ruby (at least, it greatly simplifies using the API for my needs). This was created in part for C4L and partly because I’m moving access from Z39.50 to the API when working with LF and I basically wanted a be able to do the search and interact with the results as a set of objects (rather and XML).
Anyway, the first version of the gem (which is slightly different from the code first posted prior to C4L) can be found at the project page, here: http://rubyforge.org/projects/wcapi/
–TR