Apple has announced that it's suing HTC on 20 counts of patent infringement, all of which relate to the iPhone, its user interface, its underlying architecture and its hardware. Android isn't mentioned in the press release, indicating that the interface reference in the lawsuit perhaps relates to HTC's Sense UI.
There's a quote from Steve Jobs, Apple's CEO, who says with characteristic frankness: "We can sit by and watch competitors steal our patented inventions, or we can do something about it. We've decided to do something about it. We think competition is healthy, but competitors should create their own original technology, not steal ours".
This might just be Apple trying to get the wind up its competitors who are thinking of building iPhone-esque handsets with Android on instead, or it might be something more serious. It might, of course, just be a way to try and get HTC to hand over some of the cash in patent licensing. We'll update you when we hear more.
UPDATE: HTC has returned volley as expected:
“HTC is a mobile technology innovator and patent holder that has been very focused over the past 13 years on creating many of the most innovative smartphones. HTC values patent rights and their enforcement but is also committed to defending its own technology innovations. HTC only learned of Apple’s actions this morning via media reports, and therefore we have not yet had the opportunity to investigate the filings. Until we have had this opportunity, we are unable to comment on the validity of the claims being made against HTC.”