I've gotten much better with the 100 pushups program (I'm neither willing nor able to spend money on a trainer or gym, not with this new roof on my house).

Susan, if you have an iphone, the 100 pushups iphone app is great. It keeps me motivated.

Try it, and start with girl pushups if you have to. I still do a combo of girl/boy (horrible term!) pushups, and I'm up to 52 total (but not straight). I see a big difference in my arms in both definition and strength. And it takes about 7-10 minutes out of your day.