Merge iTunes accounts

I just purchased the iPhone 5 and had to set up an Apple ID. I used a different e-mail and password than the one I was using for iTunes on my Mac. As it turns out, I now have a new iTunes account on my phone.

Is there a way that I can merge my 2 iTunes accounts? The iTunes account on my Mac has a balance left on it and I would like to be able to access that account on my phone so that I can make purchases.

Thanks in advance for the help!