Search Engine Optimisation work and Content Creation

I'm looking for help to optimise few websites (and maybe more later, as I am in charge of various websites) for SEO purposes:

I'd like the bidder to perform initial optimisation and write ongoing content such as news articles and other updates, and look at other areas that might help with the ranking on Google, Yahoo and MSN. I would provide login details to each website hosts, and you'd be expected to improve content and tags, meta descriptions etc, as well as possible help with social media optimisation on Facebook and Twitter, etc.

The right application would need to provide a clear outline of their strategy, timeframe and costs.

Also are there any guarantees (such as "page one on Google after 3 months") possible, and can you please outline what confidentiality agreements you might offer.

I have not specified a cost yet as I'm interested to find out how much such a task would cost, and we can go from there.

Thanks,
Roland