Question : two devices handing out DHCP on a network

I have a network with the common 192.168.1.x subnet.

I have a sonicwall that hands out DHCP in the range of 192.168.1.50 to 192.168.1.70 and I have a Linksys wireless router WRT54G  on the same network handing out DHCP in the range of 192.168.1.71 to 192.168.1.90

I have a Windows server 2003 on the network as well as some macs and pcs running OS X.5, Windows 2000 and Windows XP.

When I put a computer on the network (wirelessly or wired) with a dynamic ip setting it picks up it's ip address from the Linksys. That's okay with me because it seems to work, but I was wondering:

A. Is this okay, as long as the ranges don't conflict?
B. What determines which one gives a new device an IP address?
C. Is there a way to make the Linksys only hand out DHCP on wireless connections?

Answer : two devices handing out DHCP on a network

DHCP is a broadcast protocol and as such relies on a response from a DHCP server to initiate the process of obtaining a lease, as well as for lease expiration/renewal.  

Because of this, the first DHCP server to respond is the one the client will use. There is no way that I know of to segregate out responses from 2 servers on the same subnet, it's purely done by who responds first to the initial request.