Just had a meeting with Splunk's VP for EMEA. One of our technicians is rolling it out for a huge retailer in the UK at the minute and it is a fantastic product.
You can use the full version for free with a few caveats but I would definately recommend anyone who doesn't want to trawl through endless management / log consoles trying to find things when you can have a search engine akin to how google searches the web for free!
You can download it here; Splunk : Download Splunk 3.4.6
It is available for Linux, Mac, Windows (2000-> Vista).