IBM upped the stakes in an ongoing contest over corporate email software with a program that offers business partners <A HREF="http://news.zdnet.com/2100-3513_22-6055898.html?tag=zdnn.alert">up to $20,000 to dump Microsoft's Exchange</A> in favor of IBM's Lotus software on Linux. Dubbed "Migrate to the Penguin," the latest IBM incentive plan is an expansion of its Move2Lotus program, which is aimed at winning over third-party consultants and software resellers that work with Microsoft's Exchange. IBM is offering a limited-time rebate for IBM partners that move customers from Microsoft Exchange to Lotus Notes and Domino on Linux. The offer gives $20 per licensed Exchange user, or "seat," maxing out at $20,000.