Here are a bunch of links I recommend, sorted into a couple of categories:

Vegetarian sites:

Vegetarian Low-Carb - a firsthand account & advice:
immuneweb.org/lowcarb

Eating out as a vegetarian:
vegetarian-restaurants.net/index.html

Low Carbohydrate sites:

A Vegetarian thread on a Low-Carb discussion board:
forum.lowcarber.org/forumdisplay.php?f=109

Transcript of a 2004 Documentary about the Atkins Diet:
abc.net.au/dimensions/dimensions_health/Transcripts/s853516.htm

Fantastic Foods - great range of low-carb convenience foods in US, sadly not available in Australia
fantasticfoods.com/index.php

Best Low Carbs - recipes, advice etc (US):
bestlowcarbs.com

A la Carb - as above, recipes, products, advice (US):
alacarb.com

Australian and New Zealand Local Resources:

Atkins Australia official site:
atkins-australia.com

Aussie Bodies - "Protein for every Aussie Body"
aussiebodies.com.au/qandas/vegetarian+diets/default.htm

Aussie Soap Supplies - Stevia Drops Supplier (honest!)
aussiesoapsupplies.com.au/cgi-bin/jude/catalog-jude.pl?75

Pass The Toast - Many low-carb essentials for baking, sweetening and more. They sell WPI (Wheat Protein Isolate) and other ingredients that make it possible to make your own bread that's low-carb.
passthetoast.com

Empower Foods Australia - bake mixes, tasty muffin mixes etc
empowerfoods.com.au

Low Carb Australia - general advice, links
lowcarb.com.au/oz

Low Carb New Zealand - recipes, advice and links
lowcarbnz.co.nz

Sunsol Australia - makers of LSA (Linseed, Sunflower and Almond Meal), which you can buy at Coles.
sunsol.com.au/recipes/lsarecipes.htm

Soy Products - makers of the very useful and reasonably inexpensive Soy Compound that I buy at my local Coles Supermarket. It's not nearly as low carb as specially-developed products such as WPI, but it's less expensive and the fact that you can buy it at the supermarket is very convenient. I use it for thickening vegetable soups - it also makes the soup VERY filling as it's so high in protein.
soyproducts.com.au

Massel - makers of the best stock cubes in the world. They do "beef style" etc that are completely free of animal products (good for people worried about BSE, even if you're not a vegetarian). They're an Australian company, but you can buy their products in many countries. There are loads of great recipes on their site too.
www.massel.com.au/html/

Bodhi's Breads - This Perth bakery does a range of low-carb products now. I think their best is the low-carb flatbrot, which make great mini-pizzas.
www.bodhi.com.au