Have a setup with two PCs, the client has a Belkin USB wireless adaptor and the host has a DSE WLAN IEEE 802.11b. Both PCs are running Windows 2000 Pro, and the host is running ICS to provide internet to the client.
When the network is up and running it works well. Both PCs can talk to each other and share files etc, and the client can access the internet.

However, for no apparent reason, the network just stops at random. Normally what happens is I will go and look at the wireless adaptor utility on the client, and do a site survey. It shows no presence of a wireless signal from the host PC.
So it appears that it is the host that is dropping.
I did some searching on the net about this and I found a similar problem that someone else was having, they reckon they fixed it by enabling wireless authentication 802.1x on the client. I did this and it didn't seem to make much difference.
When the network is up and running it's great - it's just when it drops off at random that it's a pain.