Hell yes, of course women can be funny...and what kind of sexist question is that?!?
This is actually a very interesting question to me, Vanilla, because I just read an article that said essentially that "men tend to be the ones who make jokes and women tend to be the ones who laugh at them," possibly because funny men compete for a woman's attention during mate selection. Here is a preview of the article in Scientific American:
The Humor Gap: Men and Women See Laughter Differently in Romance: Scientific American
Yes, I read Scientific American in my spare time.

As if anyone had to wonder about that.
I tend to view such sociobiological claims with skepticism, but at least the researchers did provide some data based on studying women and men's responses to humor and gender.
The article went on to say that men supposedly don't feel a funny woman (a comedian, for example) is more desirable because of her sense of humor, but women tend to really like funny men. I know finding someone who "made me laugh" was really important in a mate, so maybe there is some truth to that. When all else fails, at least if he makes me laugh something is working! Maybe men don't look for humor in women as a top priority? Maybe they look a little lower?
However (says the article), once *in* a relationship, men really value a woman who uses humor to help relieve tension. This ability, by the way, is my one biological asset, and is probably the main reason I was able to remain humorous throughout the rising tension of numerous failing relationships.
I find women and men to be equally funny! So I voted yes.