Various SOAP vs REST debates rumble on.
It is good to see some sanity remaining: Middleware Matters: SOAP vs. REST -- huh? (Steve Vinoski)
1+1 = 0 (Christopher Ferris)
For information about SOAP see W3C SOAP 1.2 and SOAP Discussion.
For information about Representational State Transfer (REST) see the REST WiKi, in particular see Roy Fielding's dissertation and Fielding and Taylor's ACM Transactions on Internet Technology, Vol. 2, No. 2, May 2002, Pages 115 - 150 article.