I just use excel, but if you don't have that then you could download OpenOffice for free and do the same thing. As far as an online service, I am sure there are some but I don't know what they are. Besides, I don't know about you, but I wouldn't want to store all of my accounts and basically my entire business on some third party website, seems like a recipe for disaster.
Of course, I am paranoid, so maybe others would be more comfortable with that?