I bought Meprolight sights for mine - part # ML-21516. I had my dealer use his pusher to install them (charged me $10). They are essentially USP Tac sights with tritium dots - virtually identical. And yes, they are the tall Tac sights (for silencer use). I think Heinie (sp?) makes a non-adjustable tall set for the Tac that are a snag-free design, if you plan on carrying it concealed (good luck!).
ETA: The Mepro's aren't cheap - I think they were around $120 if not more.