Joe Mania Trains
Yahoo Standard gauge discussion group
Marc's Standard gauge blog
Train Collector's Association
Colin Duthie's Web Site
Standard Gauge Module Association Homepage
Other links of interest:
RailServe.com: The Internet Railroad Directory - Guide to 13,000 rail-related websites including train travel, model railroading, railfan resources, train simulators, and railroad industry sites.
Place - A haven for collectors and devotees of The Old Dimestore Christmas
Houses, and an online museum of holiday history and more! Check out the vintage Xmas photos, they are great!
Trains And More Freight Hobbies - Lots of links to informative web sites
focusing on model trains as a hobby. (Thanks for the "heads up" Derek!)