After another fruitless search of the internet for a tutorial, I decided to work it out for myself (apparently, maths can be used for other things besides working out how much fibre I need to order and how much it'll cost!)
So, after lots of measuring, re-measuring, dividing and multiplying, I ended up with.... 2 foam rectangles as resists for a camera case and ipod case.
I won't pretend I ended up with 2 perfect cases after my first try, but they turned out okay and I found they are easy to adapt.

I re-did the camera case a couple of days later with 4 thin layers, and got the size and thickness I wanted.

If you'd like to try making a case with a flat resist, I made a picture set on flickr, here
And if anyone has any tips for making cases- I'd love to hear about them.
I also made a very simple camera case by sewing 3 pieces of felt together yesterday, and made a photo set for this on flickr, too

I must say thankyou to Linda from craft gossip who did a really nice article about me and my felted vessel tutorial :)
And if anyone has any helpful how to's or tutorials they'd like to share, please leave a link in the comments, I'd love to see them :)
I don't know anything about knitting so don't feel qualified to judge that section's instructions, but I've looked through all the wet felting and needle felting projects, and there are some major problems with this book.
