A company memo from network provider AT&T seems to be the cherry on the cake of rumours about a 3G iPhone.

The US iPhone peddler has told its staff that it will not be able to grant vacation time between June 15th and July 12th "due to projected increased traffic and an exciting new promotion/product launch".

The memo (leaked to Boy Genius Report) stated that while the company would stand by pre-approved vacation time where rescheduling was not an option, no other applications for time off would be considered.

A similar memo was also leaked to Boy Genius Report last year around the time of the official launch of the original iPhone. On May 5th 2007 AT&T informed employees that because of the launch of the iPhone they would need all hands on deck between June 15th and July 15th “to ensure adequate store staffing”.

This time around AT&T didn’t say right out whether or not it was an iPhone related event but they did urge employees to try and blow last summer’s sales figures out of the water.

“Thanks to your hard work, we experienced excellent sales during the mid-summer period. This year, the numbers you produced in 2007 will be hard to beat; but as a business, we must rise to the challenge, and make every effort to exceed last year’s sales results. Your management team is counting on you!

We’ll meet the challenge “head-on” by providing an exciting Summer Promotional Launch to enable your sales to soar. We again anticipate heavier than normal customer traffic in our stores, providing an excellent earning opportunity for every front line retail sales consultant (RSC) in company owned retail stores.”

Click here to read the full memo.