Currently it has a promotion running through 3/31:
Earn 1000 pts for enrollment (but you need a referral code). You can check
out this post http://www.flyertalk.com/forum/american-airlines-aadvantage-pre-merger/1557011-business-extra-valentines-day-referral-offer-2014-a-12.html and PM FTers for the code.
Regarding how to redeem those points, you can check here: https://www.
businessextra.com/viewAwards.htm
1000 pts is enough for one-segment upgrade (650 pts) or three club day
passes (300 each).
2000 pts is enough for a coach award ticket. 2400 pts for AA gold status.
Earning structure depends on itinerary and other purchase, usually 2 pts/$10
.