A similar trick to get this accomplished. This is usefull especially if you want to install the newer pkgtools(found on soho cd in packages directory) that is already in the .txz format.
# slapt-get --install xz
# xz -cd pkgtools-tukaani-1.2.5-i586-1vl60.txz | lzma > pkgtools-tukaani-1.2.5-i586-1vl60.tlz
# installpkg pkgtools-tukaani-1.2.5-i586-1vl60.tlz
After installing 1.2.5, you can now work with .txz packages just as easily as .tlz or .tgz!
pierce.jason
EDIT: Or for converting a whole directory of txz try a for loop something like this
# for pkg in `ls *.txz | rev | cut -d '.' -f 2- | rev`; do xz -cd ${pkg}.txz | lzma > ${pkg}.tlz; done