vtap is a very good video search engine for the iphone that aggregates videos from all over the web, allows you to search for it and then encodes them and stream them to your iphone on the fly. I blogged about it here for those of you interested: http://www.search1x.com/2008/08/27/best-video-search-engine-for-iphone/
Glad to be of help! I have also compiled a list of other specialist search engines (image, videos, blogs etc). You can check it out at the Search1.x Search Engine Directory section!