- Implementation
  - Maintaining 
  - Upgrading
  - Monitoring
  - Diagnosing
  - Domain controller
    (Windows 2003 / 2008)
  - Installation Windows server
    2003 / 2008
  - Implementing mail server
  - Hardware recommendations

 - Implementation of a new network 
 - Connection to a new office from an
   old one (Share the same content)
 - Re-configuring current network
 - Security (Very important to keep
   the network secured)
 - VPN Connection from outside
   the office
 - Maintaining
 - Upgrading current network
 - Monitoring
 - Extending wired / wireless network
 - Hiring new employees will require
   more workstations or
   sharing current workstations

As you may know already, the Data is very important and you must keep it backed up.
There are different ways to back up the data, its always suggested to keep the data backed up on 2 different locations, locally and remotely.
Monitoring the backup progress and making sure its backed up properly.