Well Nokia has somewhat come to the rescue of iTunes Plus fans with the release of its new Nokia Media Transfer beta 1.0.
This smoothes the waters between iTunes, iTunes Plus songs and some Nokia smartphones on Mac OS X.
What this tool does is allow you to treat your Nokia N-Series (or E-Series as I will soon point out) mobile phone as an iTunes syncable device. And when it detects iTunes Plus (ie, Purchased) songs, it automatically retranscodes them using QuickTime before sending them to your phone via Bluetooth and USB.
Note: If you're a purist you are NOT going to be impressed with this solution. Examination of the file Media Transfer creates (by Bluetoothing it back to the computer) I noticed its a re-transcoded to 128kbps MP4 file with no metadata at all. This is not the lossless re-wrap I expected. I'll cover how to fix Nokia Media Transfer's behaviour soon. (This may appeal to some people: the Apple fingerprint seems fully stripped from the file though.)
This is a somewhat clean solution in that only songs that you want to send to your phone are transcoded, and you only ever have one copy of a song (the original, safe, purchased copy) in your iTunes library. However it does mean the sync process takes a little longer, but since the sync process is automatic, it's a dramatic improvement over the manual process.
So this is an alternative solution for Mac OS X users -- Nokia's music tool for Windows will likely achieve the same end (users yet (someone might fill me in...).
However I notice it's not perfect... Nokia's tool doesn't export phone-compatible metadata tags to my E61 (groan!) but guess what, I've got a solution for that coming too.
Download Nokia Media Transfer from http://europe.nokia.com/A4423134.