By Kasper Jade

Published: 11:00 AM EST

With the first phase of the iPhone 3G launch in the rear view, Apple Inc. is now shifting much of its focus towards product refreshes targeting its two other revenue drivers and is advising resellers to be prepared for product shortages in the interim.

More specifically, the Cupertino-based company in recent days issued an advisement bulletin to some of its channel partners hinting at a manufacturing ramp down of iPods and certain Mac notebook models, which will result in limited supplies of those products in the coming weeks.

To best address this situation and assure ample supplies for new customer orders through August, Apple "strongly suggested" that resellers bring in -- or place immediate lump orders for -- approximately 4 weeks worth of their top selling iPod models. Supplies of the players would start to become extremely limited in the next seven days, the bulletin said.

Similarly, the company also advised resellers that it would be in their best interest to place at least 3 weeks worth of orders for existing Mac notebook models. In this part of the communication, Apple is said to have specifically identified 13-inch MacBooks and 15- and 17-inch MacBook Pros, but made no mention of the MacBook Air.

Based on past experiences and knowledge of their own inventory sell-through, those resellers who received the bulletin believe the notice is a strong indicator that Apple will begin introducing its holiday consumer electronics and Mac offerings sometime in early to mid-September.

Indeed, recent anecdotal evidence has suggested Apple is readying new models of both the iPod nano and the iPod touch. A report from AppleInsider earlier this week also provided an update on the company's redesigned MacBook and MacBook Pros, noting that shipments were unlikely for at least another 6 to 8 weeks.