I've written a little manual for configuring your opsmgr or Essentials so you can collect and generate alerts based on syslogs.
In my example I used a fortigate firewall but you could use whatever network device or unix machine that can send syslogs.
Have fun,
Alkin
Read the complete post at http://scug.be/blogs/scom/archive/2008/06/16/collecting-syslogs-with-opsmgr.aspx