Unfortunately, this is typical of the posturing and pandering that goes on in our government. This proposed tx is .01 percent, a penny on every hundred dollars. The first problem is that it is not nearly enough to make a difference, despite what this article claims. Secondly, most of the speculating is done by the big banks, whose trading remains largely unregulated, and who could easily make up for whatever extra costs they incur.
Most likely this tax wouldn't deter predatory speculation. Either the difference will show up in gas prices, or just be assumed by the speculators.
http://www.jwjblog.org/2011/05/tax-on-oil-speculators-introduced-in-house/