Thirty years ago I bought many huge 9600 baud modems and did software conversions from assembler and COBOL from one computer vendor to another. All conversions were long distance and they were accomplished at the agreed price.
Today, any company not considering converting to Open Source and web standards - should reconsider their situation.
Today, my recommendation is to rewrite rather than convert. HTML, CSS and XSLT and other languages make it far faster to replace an aging terminal user interface. MySQL and XML can replace a majority of your expensive database requirements. And, PHP ties presentation together with the data. PHP also handles most of the system interface needs to keep your shop a happy place.
Whether yours in a major conversaion activity or a small new development activity, just send me an email. Your Open Source costs will be low and I'll give you a fixed price bid to get you where you want to go.