application automatic roll out

Hi,
I need help on the best way to automatically push out some application updates to users when they log on instead of going round to do it manually on indidvidual workstations using scripts and batch files.

Such applications include updating our e-mail address list, antivirus and some other regular routine task on the network.

My NETWORK Operating system is NT Ver. 4.0 and desktop o/s windows 98.

Thanks.