... it really depends what kind of web service you are going to write as well I think ...
Well, the rest of the project brief talks about XML and inter-device operability (the service has to be accessible via a PDA, cellphone, text client, stuff like that), and has to provide "useful content".
My initial thought was to write a CMS of some sort, to publish stuff online, with XSL stylesheeting to render the pages for non-standard displays. I don't know if that counts as a web service, mind .. *grin* ..
Thanks for your reply - it's given me some useful things to think about.