Here's some ponoko friendly color palettes for three design applications:
They're all compressed to .zip so you'll need to uncompress them before you use them. More then likely they'll also work with newer versions but I haven't tried. All the colors are labeled from light to heavy and whether it's used as a stroke or fill.

Application: Illustrator CS3 File Name: ponokoswatch.ai.zip Download Link

Application: Inkscape File Name: Ponoko.gpl.zip Download Link

Application: Corel Draw X3 File Name: ponoko.cpl.zip Download Link

Originally posted on the old forum (Jul 24th 2010)
Files also attached below if links above aren't working.