Once you've got the necessary cables and you've verified compatibility, you're ready to charge everything via USB. You could use your existing iPod/iPhone charger, but its single USB port means you can only charge one device at a time. Thankfully, there are plenty of products that have two or more USB ports on a single wall-wart.
If you only need to juice up two devices, something like the Belkin Dual Rotating Charger (bottom middle) is a good choice. In addition to travel-friendly foldable, swiveling power prongs, it includes three charging cables (iPod/iPhone, mini-USB, and one that works with earlier iPod Shuffle models), and it's widely available for less than $25. (The similar Griffin PowerBlock Dual Universal--at the top left--is cheaper, but it doesn't include any cables.)
If you need to double that capacity up to four ports, you might consider the Kensington 4-Port USB Charger. But another alternative is the Lenmar ACUSB4 AC Travel Adapter (top right)--it's basically the same as the Kensington, but it includes snap-on adapters for international plugs. I've been using it to charge multiple phones and iPods on my desk for the past several months, and it's worked perfectly.