If you want a good networking plus security read Cisco Safe BluePrint for SMR and try to get training on CCNA ( ICDN + Intro ) and CCSP ( SECUR - Securing IOS Networks; CSI - Cisco Safe Implementation; CSPFA -Cisco Secure PIX Firewall Advanced; CSVPN - Cisco Secure VPN and CSIDS - Cisco Secure IDS). I now that my answer seems a bit Cisco Centric but the fact is that their security training is more universal than microsoft.
My last advice is subscribe security mailing list, don't be afraid to ask around to your fellow coleagues in the Internet ( carefully don't reveal your Public IP, never send complete configuration to anyone etc (I Know I sound like a lammer=) and browse around in websites like astalavista.box.sk; www,cert.org etc.