The guys from MacRumors have discovered that Apple owns the domain: iSlate.com since 2007, and the Trademark too.
iSlate.com
iSlate.com currently points to no website. Apple is rumored to be announcing an Apple tablet in early 2010 and given this evidence “iSlate” seems a likely candidate for the device’s name.
iSlate, Registered Trademark by Apple
iSlate had been registered as a trademark by an unknown Delaware company by the name of Slate Computing, LLC in November 2006. iSlate had also been registered as a trademark in Europe using a law firm that Apple employs. The implication being that Apple set up Slate Computing, LLC as a fake corporation to secretly acquire the iSlate trademark. Apple has been known to do this in the past. For example, the iPhone trademark was originally filed by Ocean Telecom Services, another anonymous Delaware-based company.
There is evidence that Apple is indeed behind Slate Computing, LLC and the iSlate trademark. The trademark application documents for the iSlate reveal the signatory being one Regina Porter, who happens to also be Apple’s Senior Trademark Specialist as shown in her Linkedin profile. (source)