For saving ideas for color themes I use COLOURLOVERS.COM. Its great for saving colors for your house, websites, and even art :)
I mostly use it for palettes that I don't want to forget... Like colors/themes that have attracted me in the past. I suppose you could do this all yourself with photoshop, but this site makes it fun. Its a nice community with no obligations. You even get to give colors their name if nobody has discovered/used them yet!