If you don't fancy paying $29 for the official iPod charger and another $19 for the dock connector, you may like the Sonnet USB Power Adapater for $19.
The charger includes a USB dock connector cable for connecting your iPod to your machine for syncing—in case you've lost the one that came with the player. Comes in black and white to match the color of your 5G iPod and MacBook. $19 is always better than $48.
iPod USB Power Adapter [Sonnet via Shiny Shiny]