1. as lpopter mentioned - Qtopia desktop is the desktop component for synching with stuff on your computer.
2.
www.killefiz.de/zaurus - is a great source for mostly free zaurus apps and links to other apps too.
Also handango has a Zaurus section with paid apps - some are very good.
at
www.handango.com - go to the linux (or Zaurus) section.
3. Most wifi cards wrk out of the box - do a search on this forum in the peripherals section and I am sure you will get some relevant info.
4. You will have to be patient here - since the C3000 has a different processort from the older machines - hance all those new ROMs (like Cacko etc) will have to be tweaked and recompiled for the new platform - and that will be after the source for C3000 roms have been released.
5. There should be an email client on the default ROM - which does POP3.
Go to the email app - menu -> Mail -> Account and add a new account
setup the accoutn name, SMTP server and Incomming mail settings etc and you are good to go. Be sure to put in the settings with you get from your ISP.
On the settings page - add a Wireless LAN card entry and set that as the previous poster mentioned.
Once your wifi setting is enabled and email is working, the browser is just a question of launching and going to the address bar, type in a URL and bingo...
All the best and have fun and enlightenment