I've used Citeseer
extensively in my MPEG research.
I read today in Wired about a new, similar effort as well:
The Public Library of Science
I'm not sure about how other people feel, but personally, I am tired of reading papers from public universities which are vague summaries to the effect "we know this and you don't". What happened to publishing findings so that others could duplicate and extend them? Welcome to the bizarre world of 'intellectual property'.