Personally I used Picasa from Google. There are two ways you can use Picasa.
1) Simply use it as their online album. Where you can upload and manage pictures.
2) Install their application on your PC and manage your entire collection.
I personally use the second option. I have Picasa application running on my Notebook. It scans and shows me a visual catalogue of all the pictures. I can then add tags, comments etc. AND the best part is, it will automatically update my Picasa web album too. You will need Google account. Any account with any of the Google services is fine.
Just a side note, currently I have about 7,000+ images that I comfortably manage using Picasa.