AT&T Cell Phone - Manual (Page 13)

Push to Talk
Push to Talk (PTT) lets you view the availability of family, friends or co-workers
before you call.
Add a Push to Talk Contact
1. On the Home screen, click the Push to Talk icon.
2. On the PTT Menu screen, click Add Contact.
3. Type the contact information and click OK. Your BlackBerry Curve
will now send the invitation to your new contact.