Mega-store Wal-Mart (along with Sam’s Club) will join Best Buy in offering Apple’s iPhone 3G to their customers just days after Christmas, according to new reports. It’s strange to wait until after Christmas, but that’s what will happen, according to some leaked memos to employees.

In an email to clients on Wednesday, JRPG Research analyst Jamie Townsend said his firm has reason to believe that Wal-Mart will begin stocking the touch-screen handset for widespread sale to Wal-Mart customers by the end of December.

It’s expected purchase of an iPhone will still require a two year contract with AT&T and is likely to be priced the same or slightly less than at AT&T or Apple stores.

The analyst, who is forecasting Apple to sell an astounding 8 million of the devices during the three-month period ending December, said the move would reinforce confidence that AT&T will be able to maintain strong new subscriber growth amid huge economic downturns in the consumer market, and greatly slowed consumer spending.

He expects Apple will be just one of several smartphone vendors that will ramp up competition in the smartphone market by discounting their excess inventories immediately following the Christmas holiday. This also could signal huge inroads among mainstream acceptance of the iPhone.