Amazon and Smashwords.
I'm working on edits for Volume 3 right now since it is scheduled to be published on the 31st.
After Volume 3, there will not be anymore installments in this series released until later this summer. I promise, there is a good reason for the long wait. Next month I will be spending most of my time working on Deprogrammed. That means that I have until April 1st to knock out my revisions on Collide. =P
And for those that have been e-mailing me: I haven't been online much lately because my dog kind of chewed her paw raw. (Picture here.) I had to take her to the vet on Monday. I was really worried something serious was wrong, but it turned out just to be a food allergy. She's now on a special diet and a few prescriptions. It is slowly getting better, thankfully. I'm working on getting through my e-mail right now. Sorry for the delay!
P.S. If you've read both Program 13 and Allegiance and you are awaiting the release of Deprogrammed this May, you should probably "like" my FaceBook page. I've already posted one teaser. (I plan on posting a few teasers over the next month.) =D