help w/ changing some default applications

[ap0x]

hi. just a quick question for those of you who have experience in this...

i want to change the default sms and email handling applications

ie, in HTC home, when a new msg or whatever comes, i want to be able to click the corresponding icons and having sms-chat open up to handle sms, and another email program to handle emails

same thing for calendar if possible

is there a reg setting? or a config program i can use?

thanks!