Will sending IMs on Google Talk count as text messages on my BlackBerry Curve?

I have a BlackBerry Curve with an unlimited data plan but no unlimited text messaging and I would like to use an instant messenger on my phone (besides BlackBerry Messenger, as not everyone I know owns a BlackBerry), but according to at&t's website, IMs from AIM, Yahoo Messenger and Windows Live Messenger count as text messages. So my question is, if I use Google Talk, will it also count as text messages or will it use up my data plan only? Thanks in advance.