Is it a credit card charge? or a hold? I can't remember but generally they put a hold on the (total amount of) funds and then actually charge you a day or so after it ships. If they ship an order in multiple lots, they have an actual charge for each lot, and reduce the hold accordingly.
I've also got a *hold* for $41.80 on my card
02/03/2012 AUTHORISATION ONLY - EFTPOS PURCHASE AT FARNELL IN ONE CHESTER HILLAUSAU $41.80
You will usually get an email with the ETA once they know when they'll get stock, and another invoice when it actually ships. Don't forget they only had 10,000 in the initial batch, with actual demand far far surpassing that