I had a similar issue with my ISP that was resolved on their end after they white listed my domain and SQL server. The firewall was causing timeout issues.
I was able to get this fixed. It had to do with the hosting company SRX firewall that was causing the timeouts. Once they white listed the site everything worked great.
I had this same issue…and it was due to the content of my post. The html of the post began with a link. When I removed the link…it posted fine. With the link, it timed out and would not post. Very strange. I fixed it by moving the link to a sentence at the end of my post. Must be an error in WordPress. I’m using 2.9.2 and the related post was at http://www.cimbura.com/speaking/wordpresschildatheart/index.php/2010/07/changing-your-perspective-2/
