Many users have asked to include "Year" and "Date added" as search rules.
Unfortunately, these information are not available on the iPhone/iPod Touch, they simply do not exist in the programming interface. There is no way to include them in SmartPlaylist :-(
Workaround for "Year": UPDATE: With v5.2 Year can be used to search and sort
Add the year in brackets to all your titles (e.g. "Hell Hound On My Trail "), then you can use it as a search rule on Title (e.g. Title contains "hell AND "). Or create a playlist in iTunes for every year ...
Workaround for "Date added": UPDATE: With v7.1 (iOS 7) you can search and sort by date added.
Create smart playlists in iTunes according to the date added, e.g. "Added last 7 days", "Added last 30 days", and so on, then you can use a search rule on Playlist containing e.g. "7".
The workarounds are a pain, of course, but there is nothing we can do about it at the moment. We have reported a feature request to Apple.