The Southern Poverty Law Center released it's 2009 report on hate groups in America. According to the report, there were 926 active groups last year which is up 4% from last year and up 50% since 2000. In addition to the report there are several interactive maps. You can use one of these maps to see how many hate groups are in each state, the name, and the location in the state. Texas has 66 hate groups, with 7 in Houston.
Here is the link: http://www.splcenter.org/intel/intelreport/article.jsp?aid=1027