InfoWorld confirms that Dell will sell and support Windows XP to consumers beyond the June 30 Microsoft sales cutoff date that Microsoft reaffirmed today, after comments from CEO Steve Ballmer yesterday seemingly indicated it might reconsider that decision.

Dell will take advantage of a licensing option in Vista Business and Vista Ultimate that lets PC makers provide XP under the Vista license, which Microsoft calls a “downgrade” license. (Enterprises with site licenses have these same rights with any version of Vista.) In essence, the user is buying a Vista license that it can apply to XP, and Microsoft can still claim a Vista sale.

Dell will preinstall XP Professional as a “downgrade” on a variety of desktop PCs and laptops, a spokesperson said, saving users the hassle of doing it themselves. The computers available with the XP option will include the Windows Vista installation DVD in the box so users can later install Vista over XP under the same license if they wish.

The “downgrade” program is available as an option on some Dell Latitude, OptiPlex, and Dell Precision systems at no charge. It’s also available as an option on some Vostro and Dell XPS gaming systems for a small fee; these systems are targeted mainly at small business users and consumers.

A Dell spokesperson said this program will be supported as long as Microsoft supports the “downgrade” program.

Although Dell will ship a resource DVD that includes XP and Vista drivers for included peripherals, it’s unclear whether Dell will ship XP drivers for all the available options. For example, a Vostro 200 desktop today available with a choice of Windows XP and Windows Vista has an option for a wireless card that will not work under XP.