The guys from Self Sufficient-ish have written an excellent resource showing 51 Organic Ways To Get Rid Of Slugs [since moved]. Who would have thought that two bricks could become an organic killing machine?

Here are some of my favourites;

2. (a pretty micarbe one) - collect loads and stick them in a blender then paint around the area that they are in with juice, its like vlad the impalier they don't like sensing death of their own kind.

7. Chuck 'em over the fence into the neighbour's garden (No I never!)

9. Roll 'em up in puff pastry, bake in a moderate oven for 20 minutes and tell the (guests, kids, vicar etc.) that they are party sausage rolls

19. Microwave them. (please note you will need to clean your microwave afterwards)

26. Learn to love them. Understand that in the eternal cycle of life, in the endless continuum of existence, they are no less significant (or hungry) than you and I, and no less deserving of love. Embrace them. Touch nirvana together.

and finally,

32. Photograph your slugs, so that they can give up garden grazing and jet off to become international models

Great tips!