OK these questions have been bugging me could anybody reassure me... Are SE friendly urls out of date for example will G still be able to index my ?id=x url's with no disadvantages? Secondly what is your view on Myspace to promote your site and have backlinks on it to your site, what is the PR of a myspace profile? Could this drag your site down in SERP or its PR? Two very different questions but i need educating on them lol!
Google can index URLs that have dynamic parameters in it, as long as the pages URL never changes. Myspace uses outbound link proxy, so you get no SEO\Pagerank value from them.
You'll still want to be careful how many params you pass along in the querystring. Google suggests only having 2 of them max, so it may be a good idea to limit yourself.