Question #1. You will need to have a wireless access point at home, ususally a router made by linksys or some other company. If you have that, you need a wireless ethernet card for your PPC, and lots of places make those. Total between those two pieces of hardware is roughly $220, on sale. If you have wireless ethernet at school, all you need is a wireless card and whether you have to use a proxy server to get online. You can set up different connections for PocketPc 2002, so you can get online at both places.
As for CF and SD memory, CF is made for both high-speed memory and I/O capabilities for your machine, like the ethernet card I wrote about above. The SD is a newer standard and safeguards your data, with encryption. If you order a 32mb SD card, some of the space will be sued for this encryption and you won't be able to put as much on it. It's a small amount of memory you lose, but that's the price of security. It may also be a bit slower. MMC cards also fit in this slot, and are a bit faster but not secure.

Is your head spinning? Mine is.
did that help? did it make any sense? Am I right? *crickets chirping*