If you use SOGCAT, the Society of Genealogists online library catalogue, expect to run into problems using the upgraded Internet Explorer browser (IE7) released last week. SOG are aware of the problem and have posted a warning note on the site. I found the search still worked, but two warnings were issued at various stages before the search terms could be entered and results read. The new Firefox (2.0) browser has no such problems.
UPDATE: As of November 17 this problem is reported fixed for the SOG catalogue.