There are different approaches to Aikido weapons: from no weapons to a lot of them.
Probably Iwama style is the more weapon oriented version of Aikido. At the dojo i train about the half of training time is weapons training. The main weapons are jo (about 130 cm. staff) and bokken (wooden sword). Some tanto (knife) and more rarely shuriken (darts).
Here are two clips of typical Iwama style weapons techniques:
http://www.iwamaivanovo.ru/video/bukiwaza_2005.wmv (lol at 0:54)
There are another Aikido styles with weapons training. The schools "founded" by people like Saotome, Chiba, Tissier, Nishio, Hikitsuchi and more others have weapons training to different degrees. There is not, afaik, an official Aikikai position about the weapons in Aikido training, and the techniques don't share the same sources. Some are from the founder, some from previous experience and/or crosstraining in weapon arts, some developed by the instructor...
So i have seen Aikido with bokken, jo, tanto, wakizashi, bo, hanbo, tambo, tessen and shuriken.
The weapons training you can receive in Aikido will vary depending the affiliation of the instructor and his personal preferences.
I hope this helps.
BTW, i found some time ago this post in another forum. Like everything in the internet, take it with a grain of salt...