I was writing a replacement for IFI Loader awhile back.
http://www.chiefdelphi.com/forums/sh...ad.php?t=38853
It's written in Qt (Qt3, however) and should compile for both windows and linux. I used some compiler directives to detect the platform and use the appropriate pieces of code. Look for the files called serialio.cpp and serialio.h in the "loader" folder. It's a class with functions to send and recieve data via the serial port. You should be able to use it as a starting point.
I have to warn you though that I have yet to figure out why it doesn't work on Windows XP. As far as I can tell, my code is correct. When I compile it, I don't get any errors. Interestingly the same binary will run correctly on Windows 2000 and WINE, but it will freeze on Windows XP.