I want to download a good marksman and archery mod. What was the one that Todd Howard talked about and incorporated into Skyrim? The one that made arrows more powerful but slower

We believe its Duke Patricks Combat Archery http://tesalliance.org/forums/index.php?/files/file/514-duke-patricks-combat-archery/

It has a looooong readme, but best to read it thoroughly before you ask spooky any questions

Any conflicts with other mods you have installed are not going to be supported, he hasn't got time.

Its excellent though, using it myself for a long time.