Just call it as an SQL statement. I do it all the time. Instead of select * from foo use exec sp_foo. If you want to use in/out parameters, bind them up using a prepared statement.

I'll try to dig up an example around here and put it up.

Update: While delving through my hard drive looking for one of my bits of code that calls a proc, I tripped across proctest1.pl, which comes straight from the DBD-ODBC-1.14 distribution. That's a fine example. There are a couple of others in there, as well.