Frame Relay

Hi,
I have a windows 2000 Server in one state and a windows nt4.0 server in another. The windows nt 4.0 server is the headquarters.. I would like to create a better but cost effective connection(wan) between the two..Right now we have a DSL connection. I was looking into a frame relay connection(pvc,svc).Does anyone have any thoughts
on this connection or is there a better way to go. Any help would be appreciated.