Clean up HTML and CSS of website home page

Please take a look at the home page of my site [login to view URL] There have been a lot of changes since the site was designed and it has become quite messy. I would like the HTML of the home page and CSS cleaned up and checked for compatibility in all the major browsers, including IE6. I only need the HTML home page and CSS cleaned up. I don't need any design changes. I don't need any changes to the PHP. I can install the improvements myself. To help me choose a worker, then in your bid please tell me what you would do to improve the page.