Did this ever get resolved? Running into the same issue in our environment with 3.0.1.
Hi Ray,
I'm not able to reproduce this with the 3.0.1 ArcGIS Map Web Part, currently. Could you give me more details about the url you are trying to link to (web, within SP site, etc) and what the field type is (single line of text, hyperlink, etc) and I'll see if I can repro it and give you a status as to whether it might actually be fixed in the latest. I can say that we do have hyperlinks in pop-ups working correctly in the Esri Maps Web Part.
Katy