The question concerning which card to get that works best for cracking wep seems to come up from time to time on this forum so I thought it might be helpful if I posted what I have found to be the best. I spend a lot of time testing wireless Cards and antennas that work best for cracking wep.  I am surprised about the amount of cards I have accumulated over the years. I have often found that wireless antennas that connect to your laptop via USB usually work the best, regardless of trying to crack wep or just connect to an open router.  In all my testing, the Alpha AWUS036H is hands down the best I have used.  At 500mw its range and power is impressive. For Backtrack enthusiast, I should mention that its works right out of the box with Backtrack 3 final.   Most importantly, it injects packets with amazing proficiency. I am cracking 128 bit wep consistently in less than 12 minutes! You can buy it for as little as $55 and that makes it a deal compared to some set ups.  I really only have good things to say about this antenna and recommend it highly!

http://www.tuto-fr.com/en/tutorial/materiel/awus036h-alfa-network.php