Why the heck can't this old-timer Cisco router reach the Internet??

Hi

My dislike of Cisco grows :)  We just moved a client to a new location (and hence, a new external IP address).  I changed the IP address in the config (as shown below).  However, I can ping the router from the outside world, I can ping the router from the LAN, I can ping the outside world from within the router, BUT folks on the lan cannot reach the outside world.  FastEthernet0 is the external interface with a GW of .225.  Vlan1 is the internal LAN.  The IP route appears to route traffic to the outside, but no internal users have Internet access.  Please help (config portions below).

interface FastEthernet0
 description outside
 ip address 199.48.48.XXX 255.255.255.248
 ip nat outside
 ip virtual-reassembly
 duplex auto
 speed auto

interface Vlan1
 description $ES_LAN$
 ip address 192.168.1.1 255.255.255.0
 ip virtual-reassembly
 ip ospf priority 64
!
ip route 0.0.0.0 0.0.0.0 199.48.48.225

Thanks,
KMT