PDK on Linux
This should allow you to get the official Palm webOS PDK for OSX working on Linux. It's totally untested other than running a few scripts and confirming that things seem to be where they should be, so please confirm if it works for you.
First, get the command line tool "xar". Some debian based systems have it, try ipkg-opt install xar. If not found, get it from http://code.google.com/p/xar/ (I needed package libxml2-dev to compile it)
WIDK cross-compile repository is really helpful as it already has functionality to download and extract the OSX PDK, most of which will "just work" on Linux. It can also download the CodeSourcery toolchain for Linux to replace the one included in the PDK, built for Darwin.
git clone git://git.webos-internals.org/preware/cross-compile.git cd cross-compile make doctors/Palm_webOS_SDK-Mac-184.108.40.2065.pkg
You now have a Palm_webOS_SDK-Mac-220.127.116.115.pkg in doctors/ . Now let's extract it into / (this will create /opt/PalmPDK)
xar -xf doctors/Palm_webOS_SDK-Mac-18.104.22.1685.pkg palmpdk.pkg sudo sh -c 'gzip -cd palmpdk.pkg/Payload | (cd /; cpio -i)'
Now let's grab the CodeSourcery Linux cross-compiler toolchain and put it where Palm's toolchain built for OSX was
make toolchain sudo cp -r toolchain/arm-2007q3 /opt/PalmPDK cd /opt/PalmPDK sudo mv arm-gcc arm-gcc-darwin sudo ln -s arm-2007q3 arm-gcc
Someone who is familiar with the PDK should test this at this point to see if you can actually use it in the proper ways.