Porting

MacLame
MacLAME is a very quick effort to make LAME available on the Macintosh/PPC platform.
http://www.well.com/user/random/MacLame/

MicroAPL Porting Tools and Services
A range of products which translates CISC assembly-language code into optimized, high-performance RISC code including PortAsm/68K, which converts 68000 assembly language to run on the PowerPC, Intel x86.
http://www.microapl.co.uk/Porting/

Vertical Solutions
Software developers specializing in Windows to Macintosh porting; a listing of their services and an index of tools
http://www.verticalsolutions.com/

YAAF - Yet Another Application Framework
Designed to allow the easy development of cross-platform applications for the Macintosh OS, Windows 95 and Windows NT, and X Windows. Written in C++, YAAF provides a basic core framework for working with windows, views, menus, and controls in a portable fashion. YAAF is released under the GPL Library License.
http://www.yaaf.org/