As well as synch-ing all my desktop data (Contacts, Calendar, tasks etc) I have a synched copy of my mailbox. Thus, in true geek-fashion, I can, with the aid of my trusty Nokia 6310i/Palm Tungsten combination, send and receive email anywhere I wish.
Also, if you don't mind the slow speed (limitation of the GSM network) you can even browse the web with it. You'd be surprised, but some sites, such as the BBC News site and The Register, have special versions of their homepages with lower res graphics and quicker, shorter text-links, just for those of us surfing via handhelds.
In addition, if you want to be really flash (!) you could go for a wireless card and connect your handheld to a Wireless LAN for some untethered internet fun!
For applications for your handheld, their are a bunch of download sites that will give you (some free) apps for you to install and play with. Some good starting points might be:
http://www.palmgear.com/
http://www.handango.com/
http://www.pdastreet.com/
http://www.palminfocenter.com/
Or just google for "palm software" or somesuch!
HTH!