I'm using one of the MPLAB C-compilers to target PIC16's and 18's, but I'd be interested in following your progress using the SDCC. The SDCC home page indicates that getting it to work with PICs is "A work in progress". Are you part of that effort?
Nope,am not part of the effort, am using it for my project though. Well, not really true, it actually works but only limitation that it works for only a range of PIC versions but it is good enough to build a decent normal application. The installation comes with the C header files but the only drawback is that it is not for the faint-hearted as documentation is not comprehensive enough, no sample programs and maybe difficult for those new to software language. In short, one has to get one hand dirty.
Update you guys once i get it working