Doug Adams has posted an awesome new script which will make the sharing of smart playlists a simply a matter sharing a file. Expect to see this tied into the next version of SmartPlaylists.com coming soon.
From Doug's Site:
You know how when you want to tell your pals how to set up This Really Cool Smart Playlist you have and you have to scratch out something like "Artist"-contains-"Manilow" + "Last Played" - is not in the last - 6 - months + "Bit Rate" - is less than - 56 on a piece of parchment and attach it to the leg of a carrier pigeon to have it delivered?
Well, you don't have to do that any more.
Export Smart Playlist Criteria will export just the criteria of a selected Smart Playlist to an XML file--similar to the "Export Song List..." command--which any iTunes can import using the "Import..." command in the File menu. When the XML file is imported a new Smart Playlist appears in the Source List ready for action. Now, you can email your Really Cool Smart Playlist criteria to your pals, or backup all your Smart Playlists to transfer to another computer. »