You might want to check out the Inline::Basic module. It's probably no good long-term solution, but it might help ease the transition between old code and new with minimal downtime.

A lot of the specifics of converting the actual code in question depend on the specific dialect of BASIC, the way the code is designed and implemented currently, and what language-specific or platform-dependant features it uses. In the end you're most likely going to have to do a lot of hand-tuning after any reasonable conversion script.

Alan