Despite concerns that have been posted here (and in other blogs) your warranty for hardware issues on Intel Macs will not be voided for using Apple's Boot Camp Beta software. This is what System Engineer (and Mac Guru) Dane Riley, of Apple Education - West said on this topic:
I would point them to this link. Although it is not an official Apple statement we will support Macintosh systems using Boot Camp for hardware issues. We will not support Boot Camp, because it is beta, however we encourage beta users to submit bug reports. Also, we will not support Windows running on Boot Camp. Support of Windows is up to Microsoft who has not decided yet whether or not they will support Windows running on Boot Camp. Also keep in mind that this is a technology preview or beta that isn't intended to be offered for Tiger customers and will only ship in its final release with Leopard, which is expected to be discussed at WWDC in August and released in early 2007.