Just thought it was time I added this info - I will add pictures as I can.
To add pockets, i just make a rectangle 42cm wide by about 26cm high. I hem one long edge (double hemming will make it look neater and make it sturdier). I then sew it right way out, on the right side one side of the inner fabric. I just sew it to the edges first, then decide how many pockets I want, and I run a row of stitching from the top of the pocket to the bottom of the pocket (which is the bottom of the bag). I like to have three pockets on one side of the bag that are not so deep, and then I have two pockets on the other side of the bag that are deep (for a nappy for each of the boys - one pocket each :))
The lining is just exactly the same as the bag itself, but turned and topstitched. So make two bags (one is the outer, one is the inner) and then put lining inside the outer, right sides together. Stitch around the whole bag except leave a 15cm or so opening. Turn the bag the right way out. Iron the whole thing, ensuring the seams are neat, including where the bag was 'turned' the right way out. Topstitch around the whole bag :).
