yeah already seen it when its name was yagohoogle, using frame's to do the work, not a creative stuff
It's not bad. There's not a lot more you can do with the design of the site really. The only thing I may be able to suggest is find out if you can do a Google/Yahoo hack where the search results for those sites are displayed directly on your page, so that you can actually customize the look of the results.
I really don't like frames. Things look too messy. You could try to get a script to meta-search the 2 engines and display the best results.