Can I text to my iPad from my iPhone?

Yes, my wife and I do this all the time. I even text her when we are in airplanes and we have conversations while one of us is in the air. We can even send images from our cameras. Just make sure both devices are connected to the cloud with iCloud settings and use iMessage. Your text address for the phone is still your cellphone number. The text address for the ipad is any email address that you assign to it with iMessage.

Yes, with iMessage. Read this... http://support.apple.com/kb/HT3529