iPhone 2.0 can't charge via Firewire. It's one of the most annoying "features" of the new phone.
That means I've lost some chargers. Since iPhone 2.0 is a power hog, I need to be able to charge at the office.
The best way to do this would be to use my corporate laptop's USB port, but I don't want to sync the iPhone at work. That would be a disaster. The iPhone can really only sync at one machine.
One trick is to change the "sync automatically" setting to OFF at your normal sync workstation. That setting travels with the iPhone, so it applies everywhere. You can now plug your iPhone in without fear of sync.
Another trick is to hold the home button when you connect the iPhone. That's supposed to disable Sync but I haven't tried it.
Best of all is to to into iTunes preferences and click on the "Syncing" preference. There you can turn off automatic syncing for all iPhones and iPods. That's what I do at work, so I can recharge my devices from my work machine's USB port.