Apple’s retail stores began using a new voucher system on Saturday to help streamline the iPhone 3G purchase process. The voucher tickets help ensure that customers in line will have the correct iPhone waiting for them when they finally get in the store and in front of an employee.

The vouchers are handed out to customers starting at the beginning of the line and note which iPhone 3G capacity and color each customer wants. If the day’s inventory of a specific model is already sold out or accounted for through vouchers, potential customers will know before they get in the store, making it easier for shoppers to decide if waiting in a potentially hours-long line is worth their time.

Apple’s new in-store iPhone vouchers.

The vouchers also let customers leave the iPhone 3G waiting line and return later in the day to finish their purchase whenever they like. Shoppers have until 6PM the same day to claim their iPhone.

At least at the FlatIron Crossing Apple Store in Broomfield, Colorado, customers seemed happy with the new voucher system since it ensured that the exact iPhone they wanted would be waiting for them in the store. Once inside, the transaction process seemed to go quickly, too, with some shoppers completing their iPhone purchase and activation in less than ten minutes.

Apple and AT&T were hit with delays and headaches during the July 11 iPhone 3G launch thanks to account and activation server issues. While those issues appear to be resolved, the lines for iPhone 3G buyers can still leave shoppers waiting for hours to buy their combination iPod and smartphone two weeks after the initial roll out.

The voucher system appears to be a smart move to help improve the iPhone 3G buying process, and if initial customer reaction is any indication, will make a good stop-gap measure while Apple ramps up handheld production.