iPhoto organization tips?

My iPhoto library is currently 279GB and I need to look at ways to reduce the overall size of the library and/or eliminate duplicate photos. In addition to the large iPhoto library there are quite a few folders in Finder that have photos imported from a previous PC.

1) What is the best way to consolidate all photos & movies into the one iPhoto library?
2) What's the best technique to them eliminate any duplicates from the Finder folders (while ensuring the files are in the iPhoto library)?
3) Once I have one massive iPhoto library, what's the best way to divide it up into manageble chunks for easier archiving (I already use redundent Time Machine backups so that's no problem) on DVD/Blu-ray? iPhoto Library Manager SW perhaps?

Many Thanks!

This is what I would do, but I'm sure many others will differ. Firstly I would EXPORT all the photos from iPhoto to ensure that you have them all (some may exist in iPhoto and nowhere else. I would then ensure you have a backup/copy of your iPhoto file.
Then I would use a program like Find Duplicate Files for Mac*OS*X and eliminate all duplicates.
Then Either (a) sort your files into suitably named finder folders and import into an empty iPhoto album (if preferances are set correctly then an Event will be created for each folder)
or (b) import them all into iPhoto and sort them there into appropriate folders/Events

If your photos natually split themselves into large groups (ie family and professional) you could load each into separate iPhoto albums (hold down the Alt key when clicking on the iPhoto icon and you will get a choice of creating a new album - Use same procedure each time you enter iPhoto to select which Album you want, else the default is the one last used).

That strategy sounds fine but my HD is 500GB so if I duplicate each file that's in the iPhoto library via exporting, I won't have enough HD space!

Perhaps I am confused about the iPhoto library but my impression was that if you import a photo into the iPhoto library, that library would grow and you can then permantly delete any duplicates in Finder folders. If the library however is just a DB pointing to the original if you delete the original, that file then dissapears from the library as well.

It depends on how iPhoto prferences are set up (Prefrences, Advanced, Importing). Either you can import them into iPhoto in which case you can delete the originals (but I don't like having all my photos just held in one 'envelope') in which case you can delete the originals or you can choose not to import in which case iPhoto will hold only a thumbnail and a pointer to the original. Be aware that if you edit any photos in iPhoto that it will keep a copy of the ameneded photo and the original will be untouched.

As to space constraints - how about repeatedly running the deduplicate program after just exporting a number of photos - remembering to empty the iphoto trash each time. As you go on you'll be able to export more and more each time.