Apple’s homepage, which has welcomed visitors with a huge white on black advertisement announcing the new 8 core Penryn Mac Pro, was changed Monday night to something new and something vague: an announcement that reads “There’s Something In The Air”, followed by a note mentioning Steve Jobs’ upcoming keynote address Tuesday morning at Macworld 2008 in San Francisco.

The “Something In The Air” theme is also present on massive banners visible through the windows of San Francisco’s Moscone Center, where the Macworld 2008 Expo will take place starting Tuesday. Assuming they’re not promoting iTunes downloads of the old Phil Collins song, which I think is a safe guess, Apple is attempting to stimulate our curiosity as to exactly what Jobs’ will announce when he takes the stage. And they’re succeeding.

There are a number of possibilities as to what “Something in the Air” could be, so I’ll play along and speculate:

• Some new wireless capability, possibly a Wireless USB capability for the new laptop Jobs will announce at the Keynote. Yes, I said will announce, although I’m not certain about the wireless USB aspect, a new laptop was and is one of my high probability Macworld predictions.

• The addition of downloadable movie rentals to iTunes, which most of us connect to wirelessly. In recent days, Apple has been rumored be close to deals with several major studios, including 20th Century Fox, Paramount, Warner, and, ironically (considering the Disney vs. Pixar controversy from a few years ago), Disney.

• What would really make this “Something In The Air” more impressive is if the downloaded movies worked together with an upgrade to Apple TV, which wirelessly sends content from Macs and PCs to HDTVs. This may well be the most likely meaning behind “Something In The Air”.

• One item that shouldn’t be overlooked is the inevitable iPhone move to the ATT 3G wireless network. This will happen in 2008, the only question is whether it will happen in January. 3G offers enhanced download speeds and is currently only available on competitors’ smart phones.

OK Steve, I took the bait, along with the rest of the Macworld press. Don’t let us down.