you need to setup DHCP on the wireless router to serve IP addresses in the same subnet as the IP's of your router and PC, and using the IP of the PC as the gateway.
Should've mentioned that.... Do that, then disconnect your from the WiFi network and reconnect. Check that your phone's default gateway is the same IP address as your PC is binding on its network interface (i.e. that the phone routes its traffic to the Internet via your PC), and that its DNS server is the same IP address again.
I have a Galaxy S2 and all it does is "obtaining IP address from ... ". Any help there?
Never mind, I configured the IP address automatically.
I disabled DHCP on my router, I've shared the dial-up connection, I've configured the default gateway, changed the DNS server. Have I missed something?
IP address: 192.168.1.253
Gateway: 192.168.1.254
Netmask: 255.255.255.0
DNS 1: 192.168.1.100
Disable DHCP server on your ADSL router - which you've already done
Share your USB ADSL modem's connection with ICS (Internet Connection Sharing)
In Windows XP this will set the other LAN/WiFi connection's IP address to 192.168.0.1, subnet mask 255.255.255.0
Where as in Windows 7, it will set it to 192.168.137.1, subnet mask 255.255.255.0
Now this PC will act on a DHCP server on that other network interface.
Now you simply connect to the normal router either via LAN/WiFi with other network devices (eg. Galaxy S2), and then you should get an IP address in the 192.168.0.x or 192.168.137.x range.
Your Galaxy S2 should get a Gateway (& DNS server) of either 192.168.0.1 or 192.168.137.1 (depending on the ICS PC's operating system), netmask 255.255.255.0