Ok, constructive criticism it shall be.
It's not the worst PS job in the world if you're just starting out, but it's not an ad. An ad has a catchy tagline, brief or descriptive, maybe some written copy, probably a corporate logo, and a theme or idea it wants to get across, not just some photos wrangled together...(unless you're selling clothes or liquor, then all bets are off). Your pic says "iPhone 3G". What about 3G? Is it better? Faster? Cooler? Cheaper? What?
Why is it sitting in a blue whirlpool? The whirlpool is nice and all, but what does it have to do with 3G? Is it part of the corporate identity? It makes the phone look like it's meant for water, or worse, sinking in water. Generally speaking, it's best not to show non-waterproof electronics in a watery environment in an ad. Some will find it too shocking.
The screenshots behind the phones mean nothing to someone who doesn't know what an iPhone is or does. If it were a real ad, the imagery should try to have some sort of relevance to as many who see it as possible.
In the future, if you want a better reaction from the Internet People...
1. Don't tell people what they should think ("Dont you guys think this would be a good ad"). Ask hey, what do you think. Better yet, just say, here's an ad I made. Period. Fear not, people will tell you what they think.
2. Don't tell everyone you sent it to Apple and haven't heard back. That only shows that you assume it's awesome. When you tell the world something you did is awesome, you will invariably find out it's not nearly as awesome as you thought. No one likes a bragger. And even if it was the most brilliant ad on the planet, you wouldn't hear back from Apple. Apple's advertising is handled largely by Chiat-Day. Send the ad to them and you probably won't hear back from them either, but you can try.
3. Don't plaster your image with "EXAMPLE" or "no copyright". This again assumes that it's so awesome we'll all want to steal it and somehow get rich off of it. It's another way of bragging, which as mentioned, no one likes. As the poll indicates, no one will be stealing your image or getting rich from it.
If you're serious about advertising, take some classes, or find an internship at an agency. Then make some new ads, but don't post them at a tech gossip site. Print them out and show them to your mom, your aunt, your grandpa, etc. If they like the ad and understand it, chances are others will too.