The Friends Committee on Legislation provides this summary of the current legislation on Iran.

Because of the campaign season, congress will not be in session for most of October. However, the following pieces of legislation have been important rallying points for both hawks and peace advocates over the course of the last year and are likely to come up again when congress comes back into session.

The Ahmadinejad Protection and Promotion Act of 2008, H.Con. Res. 362
This bill would impose sanctions, a travel ban of Iranian officials, and block all traffic entering or departing Iran. It "demands" that the president block all imports of petroleum products to Iran by land, sea, or air. This would require the U.S. to impose a naval blockade of Iran which could be construed under international law as an act of war.

U.S. Supports International Diplomacy and Cooperation, H. Res. 1410
This bill affirms that enhanced U.S. diplomatic engagement is vital to restoring U.S. standing in the world. While this is a model piece of legislation, it only has seven co-sponsors and has received very little attention.
Summary, status, and text of H. Res. 1410 >