I might get blasted for this, but this isn't entirely true. I'm actually in the process of building a Hackintosh to replace my three month old iMac. The iMac is the Core 2 Duo 3.06GHz with 4GB RAM, an nVidia 130GT, 1TB hard drive and a SuperDrive. It cost me around $2350 after tax. For the same price I've built a system with an Intel i7 Core 2.66GHz, 6GB RAM, nVidia 9800GT, two 1TB drives (one for OS X and the other for Windows) and a LG Blu-Ray burner. When it was all said and done it cost the same as the iMac, including Mac Box Set, Vista 64-bit OEM and EFI-x (EFI dongle to get OS X running).
Does Apple charge more? Sure. Just look at how much they charge to upgrade the iMac memory from 4GB to 8GB. $1000. There is no way memory costs that much. I don't like the term "Apple Tax" though. It's branding. You always pay more for brand name. Nike does it. Kraft does it. And Apple does it. Big deal. The difference between Mac and PC i that PC has many variations creating a lot more competition than Apple. If clones of Mac were allowed to happen I guarantee you that Apple prices would drop.
But... to get back on topic (sorry about that) if Apple did this it's a bit hypocritical. Though I don't doubt MS is embellishing the story a bit.