Great series of posts here on the potential effect of Google Instant on SEO:
Yesterday Google implemented their new search experience, Google Instant and the SEO and Tech blogs lit up like a Christmas tree. It’s nice to see something get these folks excited for a change. While the notion of instant search isn’t new, Yahoo had it in 2005, Google commands the vast majority of search engine market share so such a major, public change to the Google interface warrants attention.
Essentially, in Google’s quest to improve user experience and increase speed, they’ve already lowered the time it takes to return results on a query. The actual act of searching and refinement of queries by users is what takes time, so Google Instant is designed to shorten the time it takes for users to find what they’re looking for by showing search results as you type. If you’re logged in to Google, those results are personalized as they have since personalization was implemented.
Full post can be found here: http://www.toprankblog.com/2010/09/10-resources-google-instant/