The following websites offer a wealth of information on Santurce:

gaybarsinsanjuanpr

Guide to gay bars and clubs at Paradas 18, 22 and 24 with directions from major hotels.

Babylon Gay Guide to Santurce

Miramar Historic District

arteSanturce

NYTimes - Santurce Arts Mecca

The New York Times featured an article on March 4, 2011 - "Santurce Section of San Juan Aspires to Be an Arts Mecca". 

Good overall view of the emerging arts district that has gotten even better since the article appeared.

The Tramways of Puerto Rico

Cinema Treasures

The old Fox Theater at parada 12.
Current site of Hotel Miramar.

Cinema Treasures has a wealth of information on the old movie palaces of Santurce.
More than just a movie palace, the Fox Theater hosted grand events such as Miss Universe pagents and major concerts.
The entrance is exactly where the current lobby of the Hotel Miramar is located. 

Skyscraper City

This site has forums on urban redevelopment that include several forums on San Juan, Santurce and planned development.  Many of the buildings planned during the 'boom years' will never be built, but it shows the imagination that Santurce inspires. The photo is of the proposed but never built 'Graft Tower' eco-hotel, pod residence and vertical farm!

Skyscraper City - www.skyscrapercity.com