Linux users now have an alternative APRS client to Xastir. It's called APRSIS32 for Win32. I have discovered that Lynn KJ4ERJ's Windows APRS client runs almost perfectly under the Linux OS using wine, the Windows compatibility layer.
It's pretty easy to get APRSIS32 going. Just download the Win32 version from the APRSISCE Yahoo group, save it into a folder somewhere under .wine/drive_C and run it. The program will start downloading maps so you can zoom in and set your home location. The only problem is, you can't see them. By default the maps are displayed semi-transparent and it appears that wine doesn't support transparency. So you will need to keep hitting the right arrow key which increases the opacity until the maps are 100% opaque, when they should appear. Check the APRSISCE/32 documentation wiki for more information.
There are a few screen redraw issues and the automatic updater always seems to fail, but these are minor issues. APRSIS32 uses code common with the APRSISCE version that runs on Windows CE mobile phones. These use a pretty small subset of the features available to current Windows software so by happy accident the program avoids doing things that wine doesn't support which prevent more complex programs like Ham Radio Deluxe from working.
I haven't tried the program with a GPS or a TNC as I don't have them, but since these are just standard serial connections which are certainly possible under wine that is unlikely to be a problem. Lynn seems pretty keen to tackle the problems that I have discovered. In the meantime, the program still seems to work pretty well, so if you use Linux and are interested in APRS why not give APRSIS32 a try?