Guys, I am totally new to routing and want some help on how to do this:

1. Non-openwrt router (192.168.0.1) is connected to cable modem and serves wireless clients
2. One of its wireless clients is an Asus WL-500gP (Kamikaze 2.6 kernel) router with static IP 192.168.0.51 serving it's own network of wired clients with IPs 192.168.1.x
3. 192.168.0.1 is setup with a static route to forward 192.168.1.x traffic to 192.168.0.51
4. What do I need to do on the Asus so that inbound 192.168.1.x traffic can be routed correctly? (Specifically, I have a network printer behind the Asus that all my machines irrespective of network need to access). I can ping 192.168.1.1 from the 192.168.0.x network but not any other machine behind the Asus.
5. Outbound traffic from the 192.168.1.x network through the Asus seems to do fine

Thanks in advance.

Can you install tcpdump and look at what is reaching the Asus? Since the route information looks, at first glance, to be reasonable, I have a feeling that you are having a NAT problem, either with the first router, or with the Asus.

A little more diagnostic information would help a lot.

Yes, sounds like you need to disable nat on the asus.