Here's a map:

http://maps.google.com/maps?f=q&hl=en&q=283+Washington+St.,+Cambridge,+MA&ie=UTF8&om=1&ll=42.367296,-71.097507&spn=0.026698,0.086517

From the Kendall Square T stop:

If you were travelling outbound, face the road (Main St.) and turn
right; otherwise, turn left.  Walk past a field and turn right onto
the next street, Portland St.

Walk one block and turn left onto Washington St. (it may be Newtowne
Ct. at that point).

Walk three blocks to 283 Washington St.  It is the second house on the
right after Cherry St. and has bright red steps.

From the Central Square T stop:

Walk down Massachusetts Avenue towards MIT until Main street forks to
the left.  Take your sharpest left onto Columbia St.

Take your second right onto Washington S and go one and a half blocks.
283 Washington St. is on the left and has bright red steps.

By Car:

Parking in Cambridge is difficult.  Your best bet is to park at the
lot at Bishop Allen Dr. and Columbia St., near McDonalds.

Walk away from Massachusetts Ave. on Columbia.  Take your second right
onto Washington S and go one and a half blocks.  283 Washington St. is
on the left and has bright red steps.