Should have bought an iBook or an iMac! Actually I'm not sure about iBooks, but the iMacs have the optical connection within the headphone outlet.
There are add-on gadgets which will provide an optical output. if we wait a while I'm sure others will remind us about these. i think there's one which outputs to USB then converts to a standard optical signal. I found this one which I've not seen before - don't know if it's any good -
http://www.firestone-audio.eu/shop/p...sted/bravo.php seems a bit pricey.
There are a few others. I heard good things about the M2Tech Hiface -
http://www.m2tech.biz/hiface.html Not sure about the current price, but I think it may be under £100.
There are also some sound cards which have an optical output - though I don't know how well they work, or whether they are reasonable quality. I have an old SoundBlaster external card which should do this, but I've not been too successful with the optical in/out, and in any case the sound quality is not as good as the DAC I normally use (Caiman). You could try ebay - see for example -
http://cgi.ebay.co.uk/ws/eBayISAPI.d...#ht_2135wt_922 Mine is an MP3+ Soundblaster card - though I can only run this from my PC as I can't find the drivers to run from my laptop.