After many delays, Sony last month launched its "Portable Reader System" (PRS) ebook reader and Connect Bookstore service. There is clearly a great deal of interest in this $350 device - Sony is claiming "overwhelming demand," and has been quoting delivery as late as the end of December. There was a long discussion on TidBITS Talk back in February 2006 about whether Sony's then-hypothetical PRS would do for ebooks what the iPod and iTunes Store have done for music. Here, in partial answer to that question, is a quick look at this much anticipated device