windows server as gateway for 2 LAN Segm

i have 2 LAN Segments first one LAN A being 192.168.1.0 with mask 255.255.255.0 & second one LAN B being 192.168.2.0 mask 255.255.255.0. now say i have Win NT or 2000 server which should act as gateway for both LAN A & B. from LAN A (192.168.1.0) i should be able to ping to any ip at LAN B & vice versa. NT or 2000 machine should act as a device which seperates both LAN A & B at the same time it should act as a gateway for both LAN segments. finally i should be able to setup DHCP Server in LANA & install DHCP relay agent on gateway server (WIN NT/2000) so that clients on LAN B should get IP from DHCP on LAN A. what needs to be done on gateway machine (i.e NT or Win2k server)