That site has a bit of 'the sky is falling' bias. The bill doesn't say anything about arresting sheriffs. It merely gives federal cops the ability to make an arrest in an emergency when they see a crime being committed in their presence where person or property is in immediate jeopardy. Or if someone says, "Hey, the 7-11 down the street is being robbed", then they have authority to intervene and make an arrest. In Texas, federal cops have arrest powers for state felonies.
Here is another article of many that aren't so 'conspiracy theory' oriented.
http://www.salem-news.com/articles/apri ... ffs-tk.php" onclick="window.open(this.href);return false;
Personally, I'm in favor of keeping things just like they are.