Is there any way to change the emoticons in the standard android sms app?
From what I've been able to glean - No, it's not possible via any built-in settings in the stock Messaging app.

Handcent SMS, however can disable all smiley icons so all you see is the actual text - the punctuation characters. To do this in handcent press MENU > SETTINGS > CUSTOM STYLE > BUBBLE SETTINGS

Move thru the list of options shown on the bottom (contained within a tab with an arrow) until you see DISABLE SMILEYS. Click that and when prompted SAVE your settings.