I have 10.6.3 and the latest Netbook Installer. This is all new to me, I got the Mini last week and put Snow Leopard on it over the weekend. Originally I had an issue with the sleep image (or something like it) being too old, fixed that as per the thread I found. Now this. I'd rather have the sleep image problem.
Basically if I have wifi working (at home w/linksys router that works just fine) and I let it go to sleep, when it wakes it won't connect without many restarts of both the router and the netbook. We have 2 computers, 3 iphone/ipods and a TiVo connected to the wireless and they all work great. I've changed the channel to 11, tried disabling security, giving the netbook a permanent IP, nothing works.