how do I replace OEM dialer?

[b4u2]

I would like to use something other than stock. I disabled HTC skin and am using win mo dialer. I wanted to use Idialer which I have on phone but it keeps reverting back to win mo. I would like to try other dialers to see what I like but I am already stumped on my first try.
side notes - caller id works and in call volume control work. when call id pops up and I press answer it won't. I can call out. thanks in abvance!