Address
Location
Maiden Lane is parallel to, but just north (i.e. away from the river) of, the Strand, which runs from Trafalgar Square towards the City. It's just south of Covent Garden Market.
By Tube
Charing Cross (mainline, Northern and Bakerloo) is closest; Embankment (for the Circle and District lines) and Covent Garden (on the Piccadilly) is also close.
By Bus
Many buses run down the Strand: 6, 9, 11, 13, 15, 23, 77a , 91 and 176 according to this here map. There are a few more that run down Charing Cross Road (24, 29 and 176) and across Waterloo Bridge (1, 68, 168, 171, 172, 176 and X68) if you're coming from North or South London.