Click Me!This article on wow.com lists some tricks for cross-server grouping with specific people. If you have a friend (or someone you've met via the tool) on another server, it's fairly simple to LFG group with them, according to the article.
In addition, it spells out something that had confused me ... cross-realm damage meters are broken. Way broken. That's why I was seeing weird numbers in the DPS lists for several of my runs. While skada *seems* to be doing it right, I've been listed several times as 500-ish DPS, when in fact I do 2.5 to 5k, depending on the character.
The article hints that you will eventually be able to friend (and perhaps invite) people cross-server. WOOT!
D