Its very straight-forward, all you need to do is long press your homescreen, create a shortcut/activity that goes directly to the Wifi AP settings, what you are looking for is:
Its as exactly as you would find on the Nexus One, its just hidden from the standard menus to keep the noobs out I suppose. Hopefully they leave this in, since the cat is out of the bag!
HamNCheese has figured out that the temp root is necessary to kick things off. Its not really complex, here is his instructions:
Here's a workaround to get things working (for now)
Step 1: get root
Step 2: Add the wifi settings shortcut as posted in this thread and configure your AP
Step 3: Create dnsmasq.conf:
no-resolv no-poll server=126.96.36.199 server=188.8.131.52 dhcp-authoritative
Step 5: create wifi.sh:
echo 1 > /proc/sys/net/ipv4/ip_forward ./busybox ifconfig wl0.1 192.168.1.1 dnsmasq --strict-order --bind-interfaces --pid-file=/data/local/tmp/dnsmasq.pid --conf-file=/data/local/tmp/dnsmasq.conf --listen-address 192.168.1.1 --dhcp-range 192.168.1.2,192.168.1.254 --dhcp-lease-max=253 iptables -t nat --append POSTROUTING --out-interface rmnet0 -j MASQUERADE iptables --append FORWARD --in-interface wl0.1 -j ACCEPT
Step 7: su, change to /data/local/tmp and run wifi.sh
Step 8: (important) Connect to your AP only after dnsmasq is started, otherwise you will get weird DNS failures.
Credit to teferi for his original USB tether script.