Retrieving data from other websites

I understand that this is not *exactly* an EB question, but I'm hoping someone can help me think about how to do this.

I would like to either:
a) Validate data entered in my registration form with data found on another website.
OR
b) Lookup data on the other website to auto-fill some of the fields on my registration form.

I have access to a thin client of the website, so scraping the relevant data should be relatively easy, if I can figure out how to make it play nicely with EB. Anyone doing validation like this, or understand the jQuery Validation Engine better than me?