For my international friends, Wikipedia: the Mississippi River. They do a much better job of showing just how big the Big Muddy is, and how many states have been affected by this flooding.
WAFB's River Watch Page: one of the Baton Rouge news stations, the CBS affiliate, with the best online coverage IMHO.
CNN: Evacuations ordered in Louisiana as Mississippi River spillway opens CNN's latest report.
Map of Louisiana: the purple pin is Hammond, where I live. I work in Baton Rouge, and you can see where Alexandria and New Orleans are relative to me. Unexpectedly, you can also see where Natchitoches (where I got my B.A.) is, and the town at the top left corner whose name got cut off is Shreveport where my baby sister lives.
With that clear map in mind, here's an image of where the Morganza Spillway will flood (courtesy of WAFB).
Courtesy of WAFB, this is what it looked like ten minutes after one gate of the Morganza Spillway opened. They ended up opening two, and two more will be opened today.
Courtesy of WAFB and NASA, this image of the Bonnet Carre spillway was taken April 29th with only a portion of its gates open. All of its gates should be open by the end of today.
I'm off to go work on my fiction, so I can drop my fret levels.