this question  can start a war!
in short
Spring can be used with EJB3.0
Spring and EJB 3.0 are targeted for different need but some features of each framework  can be found in another.
if what ever you want can be found in EJB3.0 then it may be wise to use EJB3.0, because it is an standard with different implementation but spring  is a framework.
you may need rest of features of Spring which are not found in EJB3.0 then you may use spring.
so to give a good decision you must first clear what is your need? do you need a dependency injection container? do you need a integration mechanism? do you need a server side component model? ...