The Open Guide to London: the free London guide

The British Library's main site is on the Euston Road, though they also have a newspaper archive in Colindale.

The building of the British Library is worth a look if you are waiting for a train at the nearby [Euston], [St Pancras] or [Kings Cross] railway stations.

Although you need a readers pass to access the collections held at the library, the building itself is open to the public, and there are generally a couple of exhibitions happenning. In addition there is a restauant and a coffee bar inside.

As an aside, they have a bizarre domain name!