If you are looking for a more long term view of search queiries than trends/twitter then Insights is worth a look:
http://www.google.com/insights/search/#geo=GB&date=today%2012-m&cmpt=geo
Who needs google trends when you have Twitscoop?
No doubt you have heard of Wordpress, the HUGE free blogging platform. This in fact runs on it. If your upscaling wordpress mu is a great way of running multiple blogs on one box without the hassle of maintaining with updates across multiple blogs.
Further to that WPMU is a great place to find plugins specifically for MU, as well as a great 100+ theme pack that all works with MU.
With new concepts such as twitter - who knows whos listening or reading what your typing?
Worth a read.
If you have access to PHP DOM (You probably should do) then this works very well:
read and write excel data with php
If you just want a nice comprehensive class to do it then this is a very good open source solution to opening excel files in php.
Art with substance - in a car park - not your average phrase?
When you want to 301 Redirect a wp post, (for whatever reason ;[ ) This wp Plugin works niceley
componentart.com Have some very nice components if your looking for out of the box AJAX UI / Charting
Great for a paid version of Open source flash charts
Often running your HTML through the HTML Purifier is a good idea, for those seeking out of the box html purification in a nice easy to work with download.