The U.S. Fish and Wildlife Service, Division of Habitat Conservation, National Wetlands Inventory provides access to wetland mapping in both DLG3 and ARC/INFO formats, both of which are tar archived and gzipped. The data is contained in grids identical to USGS 7.5' Topographic quadrangles. The individual quad-based datasets are listed under a directory which is coincident with the USGS 1:250K quadrangle name. Which means that you need to know the 250K grid name in order to get the dataset you want.
To obtain this directory name you can download ftp://www.nwi.fws.gov/maps/nwi_data.gz. This is a 679KB "gzipped" compressed file which is about 7.5MB uncompressed. This file is ASCII text and provides a cross-reference to the different grids and gridnames. (Just ignore the directional suffix under the 100K USGS Name).
Another way is to click on the Index Map link and click once near your desired location, the next map that comes up shows the USGS 250K grids.
The NWI Data Sets link takes you to the parent directory just above the 250K directory.
WinZip® provides an easy way to extract the data files. Be sure to leave the TAR File Smart CR/LF Conversion checkbox "unchecked". The check box is accessible by selecting Options>Configuration from the WinZip® menu bar.
Alternatively, you can obtain datasets, or multiples thereof, by using anonymous ftp from a Command Window:
for arc/info export files: cd arcdata/<wetdir> or for dlg3 format files: cd dlgdata/<wetdir> or for mapcode files: cd maps