From here you can get into much of the law-related material on the Net.
All Texas statutes are on-line at http://tlo.tlc.state.tx.us/statutes/statutes.html. Cases are covered less well. If you want to browse by subject, you're probably going to have to use a pay site. If you have a specific case to look for try these:
Texas Court of Criminal Appeals
Supreme Court of Texas
Federal Materials
Somewhat more inclusive than the state materials. The whole U.S. Code is here. The federal sentencing guidelines manual is here. Fifth Circuit ( but only back to 1990) is here. Supreme Court is also covered.
Fifth Circuit Opinions only back to 1990
U. S. Code no annotations