I have used Steven Runciman's volumes on the Crusades as well as a number of Jonathon Riley-Smith's books. These historians look at the Crusades from different perspectives. If you do an internet search on Runciman, you will find some obituaries (handy for his background) but, unless things have changed, there is not as much available on Riley-Smith. I emailed him for his biography but he declined to provide me with any information, directing me to the Who's Who instead. I've also used the first of Terry Jones' television series to give students an idea of what happened on the First Crusade. I have noticed it available in my local library as well as the ABC bookshop.
the best starting point for a general look at crusades historiography is norman housley's "contesting the crusades" (2005). that will lead you into a myriad of other essentail readings. we look at jonathan riley-smith, marcus bull, chris tyerman, jonathan phillips, tom asbridge, norman housley, sarah lambert, susan edgington, john france and rebecca rist - a bright new thing who has just completed her PhD and has started lecturing at st edmund's college cambridge, as well as the old canon of runciman, erdmann, mayer etc. my email is adale@northnet.com.au. contact me if you want me to send specific resources that might kick start your search.