I spent the evening packaging up the Posix port of 7-zip for Maemo OS 2007. 7-zip is the LGPLed archive utility that supports a wide variety of formats (7z, zip, tar, gzip, bzip2 and some others)

I requested an account on Maemo.org, but until that comes through you can try it out by downloading it from here:

http://download.yousendit.com/F54098BD774B52AA
(if you're surfing on your maemo, the download link is to the right of the file name).

I still have to tidy up the package a little, but it works on my N800. But as usual, INSTALL AT YOUR OWN RISK. Full source and binaries will be available when the project is approved (but you can always grab the source at 7-zip.org in the meantime and I can send you a patch to compile in maemo if need be).

The binary is 7za and it is command line only (i.e. you need to install a terminal program to use it). Typing 7za gives a full help list. You can find html docs at /usr/share/doc etc...

Bugs/advice/comments welcome. I'll think about the GUI version in the future.