hi,
there are some interesting blogs about Dynamics AX for retail out there (a really techy one http://axretail.blogspot.de/) . Also, don't forget about partnersource. It's always a good starting point.
Unfortunately, the POS system has some bugs, and picking the right version is really important. I would strongly recommend you go with AX 2012 R2. If not, try to go with at least Dynamics AX 2012 CU3.