I stumbled upon Color Scheme Designer while I was redesigning Two Penny Parties last December and I've fallen head over heels for it. It has a simple layout, TONS of different color combinations, and best of all, is free to use. That said, if you use their site more than twice, I strongly suggest you donate a handful of bucks (minimum: $10) so they can keep their operations running. It's only fair, dear readers.
To begin, simply click on the color wheel and spin it until the color combinations you like come up. Also, click the round menu buttons above it for different variations of the same color scheme. It is completely addictive. Go on, try it. I'll wait. (*whistles, taps feet*)
Here are two color schemes I think would be perfect for a Spring/Summer Two Penny Party. The second one screams Cinco de Mayo, doesn't it?
(Both Screen Shots from ColorSchemeDesigner.com)
Once you have your color scheme, it will be a cinch to find everything else: linens, decor, candles, even clothing! I can't wait for you to use this for your next Two Penny Party! Please share your color schemes with me and I will post them to the site!