Diana+ and DianaF+ Cameras
www.lomography.com
If you are looking for a bricks and mortar Lomo Store anywhere in the world, go to the lomography website. Click on Shop. In the navigation bar on the left, click on the Global Shop Locator.

Holgas, Diana+, DianaF+, film, film processing supplies, photography supplies.
Freestyle now also has the Holga cameras in a variety of colors. They also carry the Holga 135 as well.
www.freestylephoto.biz

Holgas, Diana+, DianaF+, film, film processing supplies, photography supplies
B&H Photo Video

Black Slim Devil or White Slim Angel (Vivitar Ultra Wide and Slim clones)
Freestyle Photo Supply carries them for $30. They also make an accessory fisheye lens (available separately) for it.
White Slim Angel
Black Slim Devil

Four Corners Dark Store:
A wide variety of different toy cameras, including the Black Slim Devil camera and others:
http://www.fourcornerstore.com/

Replacement Color Gel Filters:

You can buy a little swatch sample book for gel filters to replace your Diana Flash filters. Buy the book, and then cut the filters down to size to fit. You get a whole variety of colors if you buy one. The cost is about $4

http://www.stagespot.com/cgi-bin/shopper.cgi?preadd=action&key=GELSWATCH

Bricks and Mortar Stores:
Seattle:
Glazer’s Cameras
http://www.glazerscamera.com/
Glazer's has a broad selection of plastic cameras. You can buy Holgas (some from the Holgawood collection), Holga TLR, Diana+, Diana Mini, Diana+ Instant Film back, Superheadz blackbird fly, Superheadz Golden Half, Superheadz Black Slim Devil, Fujifilm Instax 200 cameras, as well as 120 and 35mm film.