No, I'm referring to quick texts (that's actually what they're called). Maybe they came with my Handcent SMS - I just thought they came with the phone.Do you mean contacts? My phone didn't come with any texts.
Open the stock messages application and start to compose a new message. Now hit the menu button and select quick text. Instead of selecting one you need to hit menu button again. You now have the option to edit or delete the different quick texts.
I use handcent as well. You mentioned stock quick texts so I was thinking stock app, sorry . Just in case someone else wants to edit the handcent quick texts, below is how you would accomplish that task.
Open handcent
Hit menu button
Select settings
Select application settings
Select quick text settings