Talk to the hand

I've been trawling through the server logs daily while bug fixing the site and been fascinated by some of the logs that show up.
It seems that either a string of infected machines are trying to find vulnerabilities with the server this site is housed on or a deliberate attempt is being made at finding these vulnerabilities.
An example log is here:
Type access denied
Date Monday, 28 January, 2008 - 21:15
User Anonymous
Location http://xxx.xxx.xxx.xxx/admin/webadmin/main.php
Referrer
Message admin/webadmin/main.php
Severity warning
Hostname xxx.xxx.xxx.34
This just started a few days ago and I routinely block the ip addresses in question.
The attempts target varying possible database URLs that luckily, are not web facing on this server.
Just saying. 

