We have an everything data share family plan. I recently discovered pdanet for android, which is amazing. I'm using it to tether my htc hero to my laptap so i can use sprints 3g connection when there is no wifi available. Is this not allowed?
Technically it is not allowed, but Sprint will have no way to tell what you are doing unless you are over-using the tethering (downloading movies and music or streaming lots of high quality video).
No, you aren't supposed to tether. I've been using PDAnet for years on multiple carriers and I have never had an issue. Just don't stream 100gigs of netflix and I think you'll be okay.