I have a love/hate relationship with my phone - an HTC PPC6800. I can't live without it - I can check my work email from anywhere, and surf the web. While I've tried many PDA's through the years, none of them have stuck, because I got tired of lugging them around. I always have my phone with me, so therefore my smartphone has made me much more organized. My wife loves it because I can remember all the upcoming appointments. Yet, I hate it. It's UI is horrible. It locks up and needs rebooted, and I feel dirty using a M$ product.
Well, I found one more reason to like it. I can tether my Ubuntu laptop to my phone and get Internet access from just about anywhere. This howto is for Ubuntu, but it should work for any distro that uses bluez-utils. Note that I briefly tried to get my laptop tethered via USB, but I found several comments that it wouldn't work without a custom kernel module. Bluetooth is easier, works out of the box, and is much cooler besides ;-)