I am not sure about the expiring links, but i know it can be done. I was thinking add the time &date to the querystring but dont format it like that. then when it is clicked on do some calculations to see if it should be considered valid, if so download else not available.
part 2
yes it should be able to handle it, i do not have any examples or anythin that would help you out with that though...google asp wap portal and that should get you in the right direction