Experimental Mathematics http://www.expmath.org/
A journal devoted to experimental aspects of mathematical research; now available electronically to subscribers. During the open trial period it is not necessary to be a subscriber to access articles electronically.
Philosophia Mathematica http://www.umanitoba.ca/pm/
Journal devoted specifically to philosophy of mathematics. Contents starting vol.1 (1993) and abstracts starting vol.5 (1997) are available on-line.
