The www.mazinfo.com site is a nice and informative site that focuses more on the attractions of downtown Mazatlán. The have good information for both residents and visitors alike. You can also join their mailing list to keep up to date on the goings on down here. At last count (2006) the list had over two thousand members.
Mazatlán City Guide from the official tourism bureau in Sinaloa Mexico. Has some nice pictures and pointers to some resources, but as you would expect in a government sponsered site, everything is wonderful! Navigation could be improved, you always need to return to the main page in order to proceed to the next area of interest.
The Mexico Travel Guide has a section devoted to Mazatlán. There are some very nice pictures and good informative text. There are several other Mexico destinations presented in a similar style. My main complaint about this site is the number of banner ads that are presented on each page. I guess everyone has to earn a living though.
The mazatlan.com site was created by the local Internet Service Provider, RED2000, and they have done a very nice job in their presentation. If some of their text seems vaguely familiar, it is because the "borrowed" some from me.
World Wide Vacations has a page devoted to Mazatlán. No real content here, other than a list of hotels and associated hotel info to help you make a reservation.
The Pacific Pearl is a local English language newspaper that is published monthly. They have put some of their articles and other information online, and it is always a pleasure to read their fun and informative writing.
Thom McDonald has put together a page that is worth reading if you are contemplating retiring in Mexico. He talks about his experience in Mazatlán, and why you should consider it as a potential retirement destination.
The official municipal government site for Mazatlán contains a picture and welcome from the current mayor, Alejandro Higuera Osuna, and a lot of information about what the city govenment is doing for the city. This mayor really seems to care, and is working hard to provide water, electricity, and sewer lines to many of the outlying areas. You'll have to read Spanish to understand what is going on here, though.
A site created in 2003 that gives an overview of mazatlan is www.1st-mazatlan.com/, which has a good sections on some of the hotels in the area. That is some terrain on which I prefer not to tread. There is similar info about other Mexico destinations, such as Vallarta and Cancun.