For those of you patiently awaiting the Authorize.net integration option, I am getting very close. I was finally granted my test account, and the code appears to be just about complete. I am looking for one or two current theme owners who have an Authorize merchant account and would be willing to do some live testing for me. Please visit the forums and login to check out the post in the "Support Area" of the forums if you are interested.
Edit: This is now open to all visitors. If you have an authorize.net merchant account, please reply here. For your part in helping me test, you'll get a reduced license price of $45 ($10 savings) or $130 for a developers license ($20 savings).