Is there a free program that will allow me to send and receive anonymous texts on my phone?

I met someone on an online game I play, and have become friends with him. I would like to be able to text him during the day when I'm not at my computer, but I do not want to give out my phone number because we are keeping a certain level of anonymity due to the game we play together. We don't even know one another's real names. Is there a program that will allow me to send and receive text messages on my phone (for free) without giving out my actual number? My smart phone came with Skype mobile already installed. Can I use Skype mobile or something similar? Any help is greatly appreciated! Thank you!