If you're going to run perl on the windows box, then I would highly recommend DBD::ADO, if you're running the perl on any other platform, you will need to build DBD::Sybase with FreeTDS as Sybase's Openclient doesn't work with SQL Server's authentication very well at all.
Also, take a look at Real World SQL Server Administration with Perl by Linchi Shea (ISBN: 1-59059-097-X). It will save you many many hours of frustration with regards to getting perl to properly work with Microsoft SQL Server.
Jason L. Froebe
Team Sybase member
No one has seen what you have seen, and until that happens, we're all going to think that you're nuts. - Jack O'Neil, Stargate SG-1