Use the cradle with its 1-Amp power supply plugged into the back. (I have a Bold so I assume the rest is the same for the Storm version). There's a second batter charging tray that plugs in behind the main cradle rest; you can use it to swap batteries or, when you unplug it, there's a USB-A charging connection so you can use it as a booster charger. Also, there's a round rubber cap behind the cradle that you might thing is only for the charging sleeve of a BlackBerry Bluetooth headset; if you take the cap off, you'll see a shallow well with a USB mini-5 charging connection available there. If the storm works like the Bold, the handset will charge through buttons on its edge (bottom side on a Bold, back side on the Pearl); if you also want to sync, you can plug in a USB connection to the computer.
It's one of the most elegantly thought-out charging solutions I've seen on the market from any vendor for any handset.
I just got mine today, ordered it through Verizon and it was $22.49. Works as a charger or to sync with the PC. Use with your A/C adaptor and it's charge-only, use it with the USB cabled hooked up to the PC and it's a charger and sync-er.
Blackberry User since Feb 2004: 7250->8703e->8830->Storm->Curve->Storm (why?!?)->Tour->Bold->Touch