Quoting our new Attorney General:

[The Senate Intelligence Committee’s bill] would provide protections from lawsuits for telecommunications companies that have been sued simply because they are believed to have assisted our intelligence agencies after the 9/11 attacks. The bill does not, as some have suggested, provide blanket immunity for those companies. Instead, a lawsuit would be dismissed only in cases in which the attorney general certified to the court either that a company did not provide assistance to the government or that a company had received a written request indicating that the activity was authorized by the president and determined to be lawful.

Ah, it's not blanket immunity, it's just saying that it would protect them from a lawsuit if they ignored the law because the President said to.  Last time I checked the President didn't have the power to determine if something was lawful.  That was, in fact, the courts, or the congress in the case of writing a law.  The president's power is to execute the law as written. 

This is insane.  Basically this would be creating the precedent for the executive to break the law at will by simply telling private corporations to do it for them and that they were doing something legal.  We still don't even know what they did or didn't do!

The only way I'd accept some form of immunity is if the immunity required full disclosure of their actions.  Any actions not disclosed would remain subject to legal action.  Beyond that, throw the book at 'em.