Do a Google search for "barcode font 128", which is one of the more common fonts. Two of the first 3 hits are for free downloads. Install the font in your system folder, and then you can use it in XL.
EDIT: Ignore this, didn't see the "2D" portion on first read. =/
I'm analyzing the development of a QR generator, it's in early design phase, I'll post here when it come on production. But don't expect it for next week.
If you want to create 2D barcode, you can try this to draw QR Code in Excel. They provide free fully-functional trial if you're using it for commercial purpose.