Organized Walking Tours -- If you're interested in organized walking tours of the city, the Patronato Municipal de Turismo (Tourist Office; Plaza Mayor 3; tel. 91-588-16-36; www.munimadrid.es/turismo) provides English-speaking guides and routes that cover the history, monuments, and leading figures of Madrid. You can get details and buy tickets at the tourist office in Plaza Mayor. Local travel agencies also sell tickets for various sightseeing tours in and around Madrid.
For something a little more out of the ordinary, check out the program arranged by Stephen Drake-Jones, an English ex-lecturer who's lived in the city more than 30 years. His half-dozen erudite and slightly eccentric walks around old Madrid are pleasantly broken up by refreshments -- liquid and otherwise -- at local taverns (tel. 60-914-32-03; www.wellsoc.org).
Another organized program of interesting guided walks is provided by Olé Spain Tours (Paseo Infanta Isabel 21; tel. 91-551-52-94; www.olespaintours.com).
If you'd like to combine a walking tour with an eating tour, contact Adventurous Appetites, a tapa-bar tour run by two enterprising young resident Englishmen. James Fraser and Will Leonard (tel. 63-933-10-73; www.adventurousappetites.com; tours@adventurousappetites.com). Their trips depart from the statue of the bear and madroño tree in the Puerta del Sol at 8pm Monday through Saturday and cost 40€ ($50) a head. Maximum size of tour group is six.