Newbie needs basic advice

I want to set up a wireless network between my mates house and mine. The houses are about 1.2 km apart across a valley with perfect line of sight. I want to do this as cheaply as possible and was wondering if two 802.11b wireless pci cards and some home built antannaes would do the job. Where can I find good antennae designs and do some cards work better than others for this type of crude long distance network? Thanks to anyone for any info.