I like the Linksys WRT54G routers. Not the newer ones, but the older ones. Versions 1-4. You can pick them up cheap on ebay for like $20-$50.
The software that ships on the Linksys routers is lame, but you can uprgrade the firmware (software) on the router and do unbelievable things with it.
There’s a website called http://www.sveasoft.com which sells custom firmware for the Linksys Routers. It’s like $20 a year, and it is really good stuff.

Your scenario would be like this:

1 Linksys router in your house and 1 Linksys Router in your friends house. They are both connected via WDS (Wireless Distribution System)
The router in your house is simply plugged into the wall for POWER. The router in your friends house is the one connected to the internet.
They form a wireless bridge, and you would connect wirelessly to your router, which is talking to your friends router.
The ranges I have seen with WDS are anywhere between 500-1000 feet.

OR, you could go absolutely ape-shit and pull something like I did a couple years ago. Just using a common usb wifi-adapter.
http://www.wifi-networks.net”>http://www.wifi-networks.net
The range on that dish is 2-3 blocks with a clean line of sight.

Also, if it’s just 150 feet away, the wireless card in your computer may be able to reach his access point with no problems, with doing nothing to it.

You will need security, WPA2 Personal, or people like me will come by and leach your bandwidth from you, and you will not ever know