The charger and USB cable of the Pre are pretty well designed, and make charging and connecting to your Pre pretty easy and pleasant.
The charger is essentially a USB cable that plugs into a neat Palm base, so you can use the cable either for plugging into your computer or into the charger. The one end is standard USB for plugging into the charger or computer, and the end that plugs into the computer is a micro-usb I believe. The same connector that is on newer blackberry's (I haven't tried interchanging the power cables, I'm sufficiently paranoid of doing that!).
When you plug in the usb cable into the power adapter, it simply charges the phone. But when you plug it into your computer, the phone gives you a few options of what to do: you can use it for media sync (haven't tried yet, will on a later blog), use it as a usb drive or just charge it. If you don't choose anything, after a while it appears to time out and default to charge only. If you choose to use it as a 'USB Drive', the screen changes to what looks like an external harddrive and the phone is now accessible via the computer. Many of the services are now unavailable on the phone in this mode, and you don't appear to be able to use the handset of the phone either. Browsing the phone on your computer gives you access to most of the files available on the phone, and i've used this to access pictures and downloaded documents easily.
A nice feature I've noticed on the USB cable is a shiny indentation at each end. This appears to be on the 'top' of the cable. You know if this is facing up, it's plugged in the right way. The downsides I should note, about the USB to compute connection is that once connected as 'USB Drive', as I said, you do appear to loose the ability to access or use your phone from the handset during this period. Additionally, there appears to be no current means to 'tether' the phone to your computer so you can use it as a wireless modem. Granted, this is a feature most phones don't allow, but would be nice to see.