Pagination is tough, and Google has sent really mixed signals. They seem to suggest one of two approaches:
(1) Use the new rel=prev/rel=next tags (tricky to implement, and Bing doesn't honor them, but they do seem to work)
(2) Rel-canonical to a "View All" page from paginated results (pages 2+)
Adam Audette did a great post recently on pagination:
http://searchengineland.com/five-step-strategy-for-solving-seo-pagination-problems-95494
To Simon's comment, I've also had decent luck using META NOINDEX,FOLLOW on pages 2+ (although I'd definitely recommend that before Robots.txt). The only issue is if people are linking to those search pages - that's pretty rare, though. All in all, paginated search results have very little SEO value.
