As the Providence Journal editorial board recently put it, when it comes to the Taricani affair, “there are no heroes here.” Perhaps this is a glass-half-empty assessment, but the entire controversy has a feel more of competing negative claims than of balancing strong arguments.
Writing of the significantly different, but inherently related, Plame affair, Jonah Goldberg expresses one side thus:

But in all of this debate, what people seem to be overlooking is that journalists aren’t always analogous to witnesses to crimes. Sometimes they’re accomplices. Imagine that a vindictive government official wants to embarrass an opponent by leaking his tax returns. He steals them from confidential files and meets a reporter from the Times in a back alley. The reporter publishes them. It seems to me the reporter isn’t a witness, he’s an accessory. If it makes it easier to understand the point, imagine instead of tax returns it’s plans for a cheap nuclear weapon al Qaeda could make.

On the other side, consider Mark Tapscott:

The Taricani and Miller cases signify a disturbing trend of government officials’ resorting to subpoenas and criminal prosecutions to silence confidential sources, who would otherwise provide journalists with documents proving fraud, negligence or outright criminality in government.

Whether we see the line that we must walk as between important rights that we wish not to trample or between slippery-sloping pitfalls that we wish to avoid, the solution by which we tread must cover a variety of circumstances. In the case of Plame-Wilson, the journalists stand between the allegedly wronged couple and the executive branch (in one aspect or another). In the pre-Bevilacqua phase of the Taricani case, the journalist potentially stood between the executive branch and the judiciary itself. How do we balance the various claims of all involved branches (which will always include the judiciary), the journalists, and any other interested parties?
As a preliminary suggestion, intended to be honed through debate, I’d suggest that the law force the involvement of at least two branches of government. In some way or another (perhaps through the representation of the prosecutor), the executive would have to approve of court orders for revealed sources, and the judiciary would have to issue the orders. Perhaps there should be recourse to the legislature if either branch believes the other to be acting in bad faith.
As to who should be eligible to be counted as a journalist, I’m biased, of course, but I’d suggest that the answer be “anybody.” The protection ought to flow through the action, not through some ostensibly unique status of the actor. If a person receives information for the purpose of publicizing it — and subsequently behaves accordingly — then it oughtn’t matter whether the medium for doing so is given, bought, pursued, or constructed.