This label printer doesn’t work out of the box under Linux. There are some instructions over at ubuntuforums.org, but they’re missing something for the latest Ubuntu Oneiric Ocelot. These instructions should work:

1. download the DYMO SDK dymo-cups-drivers-1.2.0.tar.gz from dymo.com
2. unpack (a directory dymo-cups-drivers-1.2.0 will be created)
3. make sure you’ve installed libcups2-dev and libcupsimage2-dev (and, of course, build-essential)
4. run ./configure
5. try a make all, you will most probably get various errors like “size_t has not been declared” or “size_t does not name a type” — if so, try this:
   • add a line: #include <stddef.h> as the first line to the following files:
     • src/lw/LabelWriterLanguageMonitor.h
     • src/lw/LabelWriterDriver.h
     • src/common/Halftoning.h
   • now, again, run make all
6. run sudo make install
7. now open System Settings → Printer
8. make sure, your LabelWriter is connected
9. add a new printer, choose your LabelWriter, when asked for a driver, point it to ppd/lw320.ppd from the dymo-cups-drivers-1.2.0 directory
10. start printing, e.g. from glabels