Yup.
In Gnome:
System > Administration > Network
Select the connection you want to set up a static IP on, click 'Properties'
Select 'Static IP Address' from the drop down menu
Type in the static IP you want
For gateway, type in your router's IP
Subnet mask should be configured automatically when you tab into it
In Gnome:
System > Administration > Network
Select the connection you want to set up a static IP on, click 'Properties'
Select 'Static IP Address' from the drop down menu
Type in the static IP you want
For gateway, type in your router's IP
Subnet mask should be configured automatically when you tab into it