Legendary guitar virtuoso Carlos Santana announced Thursday he has agreed to a two-year residency at the House of Blues in Mandalay Bay Casino in Las Vegas, switching homes from the Hard Rock Hotel & Casino.  A spokesman for the House of Blues confirmed the news, noting that a short run of shows will take place in May and June, then the residency will resume in September, running through the end of 2013.  Tickets for the first batch of shows go on sale March 3rd.  Santana expressed happiness with the arrangement, adding that part of each ticket sold will benefit his foundation, which supports health, education and the arts for children.