Static IP using Ubuntu 8.04

[Rein]

Could someone tell me how to setup a static IP on Ubuntu 8.04 using a wireless
adapter. When manually configuring the wireless adapter to use a static IP it
does NOT recognise the network. Pinging the gateway results in error: network
not reachable. DHCP works fine!
I have another laptop (DELL I8200) running Ubuntu 6.06 LTS and have NO problem
with a similar setup.
I have a network with 4 computers, Each with dual booting and each with an
allocated IP address.
The manual configuration of the wireless adapter does not seem to work in Ubuntu
8.04.
Any suggestions anyone?
Rein.