Tartan Maker is one of the best places to bring your newly created color palette. Too bad it does not read an Adobe Color collection; but no matter. Seing your palette of colors tartaned together is one of the best tests to see if the compliments co-ordinate and the blends mingle and shine.
Stripes Generator allows users to combine 2 or more colors in a striped fashion. I find stripes a very effective way to tell how well colors work together. Users can set the angle, shadow, and sizing of the stripes. Its a simple but useful tool. If you want, you can share your stripes with others.
ColorCombos provides ample room to test out your color combinations. There is no support for importing your palette [its one color at a time; but you can easily move and delete colors or pick up your colors from your own or a favorite website.
Aviary has a series of Flash based tools for edit color bitmap or vector images. Be cautioned - there is a learning curve; so do watch the many available demo videos. There are so many nifty tools and effects it is hard to decide where to start.
Idee Multicolor offers a great way to test your palette/color scheme. Give it a list of colors and Idee MultiColor matches your color scheme against over 10 million Flickr images. On the right you can change, add, or remove colors from your scheme and as soon as you do so the thumbnail images change accordingly. Just great!