I'm a bit surprised this provokes a discussion. According to both Pathfinder and 3.5, "to activate a wand, a character must hold it in hand (or whatever passes for a hand, for nonhumanoid creatures) and point it in the general direction of the target or area." A claw would certainly be "whatever passes for a hand" for a raven, and the somatic usage component is simply pointing it in the general direction of the target or area, which a raven can certainly do with its claws. No problems there. As a spell trigger item, speaking a command word is also necessary, and ravens are capable of speech. So the first precondition - whether a raven is physically capable of using a wand - is definitively answered.
The second precondition - being able to cast the spell in question - varies between 3.5 and Pathfinder. In 3.5, you need to have the spell on your class list to use a spell trigger item. It also provides an example of a 3rd level Paladin (who cannot yet cast anything) being able to use a wand if the spell is on his class list. A raven does not qualify unless it somehow has class levels. In Pathfinder, the same applies, but having the spell as a spell-like ability also qualifies for spell-trigger items, so "imbue with spell-like ability" would make it work.
Now, since a raven cannot cast the spell in question, it will need to use the Use Magic Device skill to activate a wand instead. The DC for using a wand is DC 20, and the raven can use the spellcaster's skill ranks instead of its own. You can also buff or equip the raven with things like Heroism, Eagle's Splendor, and a Circlet of Persuasion. In Pathfinder you could also give it the Figment archetype or the Evolved Familiar feat and hand it the 1-point Skilled evolution for a +8 bonus to UMD.
So the short end of it is "Yes, familiars can use wands. As long as they can hold it in a hand (or whatever passes for a hand for non-humanoids), point it, speak the command word, and succeed at a DC 20 UMD check." By the way, if your familiar can't speak, it can still activate a wand through a DC 25 "activate blindly" check.