What do you mean "IC" equivalent? The SMT equiv should be something like mmbt3904, or pzt3904. 2n3904 refers both to the case style (to-92 footprint) and the semiconductor material. If you search Fairchild, Vishey, ST, etc using the parametric option you'll probably come up with something. Or search the mmbt/pzt PN's if SMT is what you need. What package are you looking for anyway?
If you need multiple xstors in a dip type package you'll most likely have to do the parametric search using the 3904 characteristics.
Good luck.