You don't need iPhoto buddy to have separate libraries -- iPhoto has the capability of handling multiple libraries. Just hold down the Option key when you start iPhoto and you will be prompted to indicate which library you want to open or do you want to create a new library. However, if you sort into multiple libraries, you will not have access to all your photos at one time. If this is important to you, a better way would be to go the folder/album route. I have folders for general titles -- Christmas, Vacation, etc. Then, within each of those I have separate albums for -- Christmas 2005, Christmas 2006, or for the vacation one, San Francisco 2005, New Orleans 2007, etc.
You can also rename your "rolls" to better indicate what is on each roll. Sort of a preliminary organization. And, with that in mind, you can move photos from one roll to another -- say you took some photos of your pet and they ended up in a roll with your vacation -- you can move the pet photos out to a different or even a new roll, allowing you to name one roll "pets" and one roll "vacation" or the like.
And by the way, stay out of the iPhoto library folder in finder. Making changes there will create havoc and you will be most unhappy. Do your organizing and anything else you want to do to your photos from within the iPhoto app itself -- NOT finder.
Good luck!
