I recently downloaded a copy of Picasa, and was very impressed. It scanned and found ALL of my photo and image files, on all of my hard drives, and made them all available on one long scrolling page. I've rediscovered pics that I forgot I had! If your photos have gotten so numerous that organizing them seems impossible, Picasa will be an excellent tool to help you get a handle on the situation.
It also offers some basic editing tools for improving photos. The program is available free of charge, and it's a cross-platform program; versions are available for Windows, Mac and Linux.
From Marziah Karch at About.com, a review of the software:
Take a Look at Picasa - Review of Google's Digital Photo Management Software[...] Picasa will organize your photos by date and initially retains the same file structure as your hard drive. The main area shows thumbnails of the images, and along the right side is a scroll bar to navigate. Thumbnails in the library are grouped by folder, but they’re all displayed (with some scrolling.) This means that you don’t have to repeatedly click to navigate to a new folder, which is a nice touch.
You can move thumbnails from folder to folder directly from Picasa, and it will confirm and then move the corresponding file on your hard drive. This makes it much easier to organize albums. [...]
It's a short review, but it gives you a good summary of all the basic functions, I recommend reading the whole thing.
You can download Picasa from the main page of their website:
Picasa by Google
