I'm in a similar environment, though we did not really start the move to .Net yet. I'm basicaly using Perl

• as COM objects from the ASPs and VB (using ActiveState's PerlCtrl)
• for services that do tasks that'd be much harder to write in VB/C
• for small scripties that need to be run on the servers every now and then and do not deserve a separate service.(There's a Perl service that serves as a "scheduler". Some of the tasks need to be run once every ten minutes, some once a week ...)
• for log mungling and parsing
• to generate VB code
• for various "hand-made" utilities

Jenda