Well just in case someone else is going to do this, I will show you my steps.
1. In iTunes, create a Smart Playlist that contains only checked songs. This can be done a number of ways. The way I did it was to use the filter "Date Added is after 1/1/1990" and check the box that says "Match only checked items"
2. Get playlistext stand-alone app from
http://www.crea-doo.at/ituneswatcher/downloads.htm (at the bottom of the list of downloads).
3. Use playlistext to export the Smart Playlist you created in step 1. You should now have a .M3U playlist file.
4. Of course get foo_skip and foo_custominfo and fire up foobar2000. Go to File >> Load Playlist... and find your .M3U playlist. It should now be in your list of playlists.
5. Go to your Preferences, open up the Custom Info settings under the tools heading, adjust your settings, and go to the Context menu commands tab.
6. Delete whatever is there by default and click New. For Display Name, type Check Me. For Field Name, type CHECKED. For Value, type the number 1. Leave the rest of the settings alone.
7. Without leaving this part of the preferences, click New again. For Display Name, type Uncheck Me. For Field Name, type CHECKED. For Value, type the number 0.
7. If you are using Columns UI, go to Playlist view under Columns UI under Display in your preferences. Switch over to the Columns tab and click Insert at the bottom left. You will have a new column. I suggest moving it to the top and renaming it to C, but it's your choice.
8. For your new column, here are the settings you should use:
Display:
$if($strcmp(%checked%,1),•,)
Sort:
%checked%|$replace(%artist%,The ,)|$replace(%track artist%,The ,)|[%album%]|[%discnumber%]|[%tracknumber%]|[%directoryname%]
10. Go to the full list of the files in your library. Highlight every song you have and right-click them. Select "Uncheck me" from the context menu.
11. Highlight all of the files in your newly-loaded playlist (from step 4). Right-click and select "Check Me".
The metadata from your iTunes checked songs should now contain CHECKED=1 and unchecked songs should contain UNCHECKED=0. I suggest backing up your custominfo database every now and then because it is annoying to figure out which songs you like or dislike out of thousands.
This topic about foo_skip is also relevant:
http://www.hydrogenaudio.org/forums/index....showtopic=30361EDIT: I would like to note also that all downloads links to foo_skip are broken, so if someone could post the latest DLL on this thread I would be much obliged.