Since a guild member turned me on to the possibilities of the cross realm raid opportunities via the website Openraid.us, I have since discovered another option via an in game addon called 0queue (that's Zero Queue).
I have used them both a grand total of about 2 days now and feel they are worthy of mention to my fellow 'zammians in case you had never heard of these options before.
In the past, I had disliked people from other realms walking my quiet and serene realm of Skywall. It made for camping rares and other such things that much harder when some jerk from another realm would steal my kill or whatnot. It is one of the things I enjoy about a relatively low population, but conversely made for joining raids that much harder.
Open raid involved creating a free acount on their website, and then logging in, browse through to find the raid you want, and post your battle tag ID. You then go back into WoW and await for someone to "friend" you and then join that raid. It works well, has a fairly substantial subscription base, but you have to do all the work outside of WoW. The main flaw with 0Q is some possible infringements with Blizzard, as the developer has a "beer" request which goes against Blizz's modus operandi. Still a legal addon, currently anyways. It is "under moderation" over at Curse.com, but I downloaded it from the developers website.
0queue is all done in game. The principal is the same, browse the raid listings looking for the one you want, or create your own. You then simply click the wait button, and your raid invite will usualyl show quite quickly. The subscription base appears to be quite smaller than Openraid (last night had about a 5000 horde/5000 alliance split on 0q, while Openraid is in the hundred of thousands. Regardless, I as able to join several Celestial raids over the evening across all my alts quite quickly. I was hopeing for my world bosses, but the majority of the raids listed (being a Tuesdady) were for flex SoO , Celestials, and Ordos.
Anyways, I have to get back to work, so that's my quick run down on those two options. To summarize, they both work quite well. Pick your poison.