(Infrared LED Circuit) Can i use this circuit with 3.3v logic?
You probably can, but you may need to change the base resistor. Remember the 4.3 volt calculation you made? Do you think you ought to redo it with (3.3 - 0.7)? 

Actually, what exactly was your calculation for the base resistor? The usual rule of thumb for calculating this sort of circuit is to set the base drive at 1/10 to 1/20 the collector current, but you have about 1/8.