unknown accounts in netinfo user list

I am a new mac person and just exploring os x (10.4) a bit... I noticed a whole bunch of users in my Netinfo Manager users list. I dont' think they're supposed to be there. What do I do about them, and does this mean I have a breach in my wireless connection (WPA/ WPA2 is enabled)? Thanks so much for any assistance!

I highly doubt it.

What names? OS X has system accounts to perform system functions.

unknown netinfo users

Thanks for the reply. The names are all random, like "unknown", "nobody", "jabber", "clavmav", etc. My user name is there as well. One has a home directory showing as home/ var/ virusmails.

unknown and nobody is the system.
jabber - are you running a Jabber IM server?
clavmav - maybe the ClamXav antivirus program?