Windows Vista features numerous new features, which are exciting and useful too. So, for XP users, let me briefly mention alternatives to much talked about features in Vista for Windows XP.
1. Search.
- Windows Desktop Search (Microsoft) : Fast, well organised, nice UI.
Size : Just above 4MB
Click to Download.
- Google Desktop Search (Google) : Fast, Traditional Web-based Google layout for Searches.
Size : About 2MB
Click to Download.
2. Sidebar.
- Google Desktop Search (Google) : Comes with it’s own sidebar!
Size : About 2MB
Click to Download.
- Desktop Sidebar : High Customizability
Size : 10.8MB
Click to Download.
3. Picture Organizer.
- Picasa 2 (Google) : Great UI, easy to use and organize
Size : About 5MB
Click to Download.
4. User Interface.
- WindowBlinds 5.1 (Stardock)
Size : ?
Click to Download.
- Windows Vista Skins
Search them on DeviantArt.
Well, enjoy then! 
