JavaScript, PHP and AJAX for Web 2.0

Hey everyone,

So I've been working on a content management system based upon PHP, MySQL and Apache. Its a pretty decent little site but i would really like to update it to work a little better with AJAX. Currently i'm not an amazing Javascripter so i'm trying my best to find a tutorial on it. i've checked out http://www.w3schools.com but i was wondering if you guys have any other sites you may suggest for someone starting out with JavaScript. i'm not by any means a new programmer but i mostly code in PHP, XHTML and CSS so its hard to get used to the way JavaScript is syntexed.

My second question is whether or not i should even keep using PHP MySQL and Apache. I've really noticed that a lot of sites these days have started to switch to ASP. The main reason i'm liking PHP is because it can seamlessly mingle with Apache and Linux servers. i'm not to certain if ASP has to be run on a Windows server or not.