My first introduction to felting wool was at the Creativfestival in Toronto. I went to a seminar on wool felting, specifically wet felting and was completely amazed and impressed.
If you've never tried wool felting, you'll be amazed at what you can make with just a few low-tech and inexpensive tools and supplies.
Wool felting can involve fulling fabric in the washing machine, wet felting or needle felting (I have very limited experience with needle felting, so I won't focus on that). They are all fairly simply techniques and don't require any complex materials.
If you are just learning about felting wool, and looking for a good resource on the subject, the book, Simply Felt: 20 Easy and Elegant Designs in Woolby Margaret Docherty and Jayne Emerson is a great place to start. It is full of clear, easy to follow instructions and has some great projects that you can try.
One thing I really like about this book is the fact that, if you're someone who really likes to follow directions, you could reproduce the projects exactly as they are in the book. But if you prefer to do your own thing, you could simply use the book as a guide for learning wool felting techniques and use your imagination to create your own projects.
The book also lists several sources for buying wool roving. There are a few sellers who sell wool roving on eBay for reasonable prices as well.
This technique for felting wool involves simply placing a pure wool item (a sweater you are no longer wearing, for example) in the washing machine on hot with a couple of tablespoons of soap. As the item is washed with the hot water and soap, it will shrink down. Once the fabric is fulled down (i.e. shrunk and matted), rinse it thoroughly and lay it out to dry.
Who knew there was a practical application for my laundry accidents?
This process for felting wool will turn your knitted or crocheted pure wool item into a matted, firm fabric that can be cut without fraying. Simply cut and sew your item into the shape you wish. You could easily turn a pure wool sweater into a felted handbag, a pillow or, if you have a few, pieces of pure wool items available, a cozy blanket.
This technique for felting wool, while still simple, requires a little more work.
1. Start with wool roving (wool that has been washed, combed and carded but not spun into yarn). You may choose wool roving that has already been dyed, or you may dye your own (I haven't tried this, but I have heard that Kool-Aid crystals sprinkled directly on the wool make great colors, or you could simply use Rit dye).
2. Cover your work surface with a waterproof cover (it will get quite wet) and then lay down something that will help to agitate the wool (a rattan blind or mat works well).
3. Take a piece of your wool roving and smooth out the strands so it is fairly loose and fluffy, but not too thin, and lay it on the blind or mat. Continue to lay out pieces of wool roving until you have something that is slightly larger than the size of the fabric you need (the roving will shrink up, and it takes a little practice to get a sense of how much shrinkage you will get). Make sure there are no holes or gaps.
4. Repeat this process until you have several layers (three is good to start, but use more layers if you want thicker felt). Be sure to alternate the direction of each layer, so if you lay out the first layer from side to side, lay the next layer from top to bottom.
5. Lay a net curtain over the layers of wool, and thoroughly wet the whole thing with hot, soapy water.
6. Simply rub the surface of the net with the palms of your hands until you have flattened and meshed the fibers. Turn the piece over and do the same to other side.
7. Wet the piece again with hot water and roll it up in your blind or mat. Roll the mat back and forth to full the felt. Unroll the blind, turn your felt a quarter turn, re-roll it in the blind and repeat this step so the fibers get meshed in both directions
8. Remove the felt from the blind and roll it in a towel to remove some of the water, then lay it out to dry.
You'll have a firm piece of felt that you can then turn into any number of different treasures.
This is just a quick and dirty summary of techniques for felting wool. If you're looking for a resource with plenty of great projects and different techniques to try, I'd recommend the book Simply Felt. It's a great starting point if you're learning about wool felting.
You may also want to check out this series of videos on wet felting a curly que. They will show you some of these techniques in action.
Wet Felting Part Two
Wet Felting Part Three