A service that works
I just discovered an OS X service that works. I was reading an article and needed to look up a word. I copied it, launched OmniDictionary, pasted it then looked it up. I started to write a suggestion to the Safari team to include dictionary look up for selected words when I thought I'd poke around at what was already implemented. Eventually I discovered that with Omnidictionary launched there is a Service available in Safari (and other programs) to look up the selected word. Works sweet (in Safari and other programs).