Biennial Flight Review is only required to act as PIC. You will be able to fly with an instructor without a BFR as much as you want... in fact you HAVE to fly with an instructor to GET a BFR. Other than that to act as PIC you'll have to do 3 TO/LND in the same catagory (airplane), class (multi/single engine), and type (if required).

http://ecfr.gpoaccess.gov/cgi/t/text...1.1.34&idno=14

http://ecfr.gpoaccess.gov/cgi/t/text...1.1.35&idno=14