Dave Ward at Encosia has made a great post on common ‘gotchas’ with jQuery and ajax/json:
http://encosia.com/2008/06/05/3-mistakes-to-avoid-when-using-jquery-with-aspnet-ajax/#comment-31182
(This includes calling webservices/pagemethods)
See also his post on jQuery + ajax on building a client side repeater:
http://encosia.com/2008/06/26/use-jquery-and-aspnet-ajax-to-build-a-client-side-repeater/
I really like the use of jTemplate – as a fan of templates such as NVelocity, this is a powerful way to build UI without the heaviness of .net controls!
As always, Encosia has some great content available – thanks Dave!