To do this setup properly, you need to configure one device at a time. This means you will have no internet access until the process is completed. As I said earlier, it may be an idea to learn how to reverse each section you change so that you can restore your original setup should anything go astray.
Start off by disconnecting your computer from the network, as well as isolating the Speedstream and Linksys (no cables in them). The Speedstream and the Linksys should be off before starting configuration. The reason this is needed it because you will have trouble accessing the routers configuration pages in the current setup. The idea here is to create small network systems and join them all together keeping it as simple as possible.
Working on the Speedstream first, connect your computer directly to it and power it up. Your computer should allocate itself an IP address and you should be able to access it's configuration pages at
http://192.168.254.254 If you can, try the guide I've found here
http://www.dslreports.com/forum/r20532881-
Once that is configured, you may not be able to access it's configuration pages - this is normal.
Next disconnect your computer from the Speedstream, connect up to the Linksys and power it up.
You can login to it from here
http://192.168.1.1
Username: admin
Password: <leave blank>
You need to head to setup->basic setup and fill in your ISPs required connection settings. If your ISP requires you to login, be sure to specify PPPoE and add in your username and password (generally your email address and password). Most of the other settings should be right to leave as auto. Save these settings and power it off.
Connect the Speedstream's LAN port to the WAN/Internet port of the Linksys router and connect yourself to the Linksys router as well (LAN port). Power it all on. If all goes to plan, your should be able to access the internet from your computer. If not, you may need to revise the settings (probably the Linksys settings as I cannot be 100% sure on the settings used by your ISP).
If you can access the internet, in order to host, you will just need to follow this guide
http://www.portforward.com/english/routers/port_forwarding/Linksys/WRT160N/Warcraft_III.htm
(Don't skip the static IP address guide link at the top)
If something has gone astray while attempting this, or you'd like additional help with a section, please let me know where.
