After your tomato seedlings develop a few "true leaves" (not the first ones that come out, but the second set) and they are getting well established, you can "pot-out" into larger containers (like the ones you get if you buy them from a market or store).
1). Fill some small pots, clean yoghurt containers etc with some good potting soil. Water until damp.
2). Optional–add some vermincompost into a hole you make for the seedling to go into (mine's not quite ready–it still has other bits in it–but I think it's ready enough to add a bit of a kick to their growing process).
3). GENTLY lift the seedling and surrounding soil out of it's original seeding tray and place into the supplemented hole in it's new home, ensuring you're getting all the roots covered.
4). Add a bit of extra soil if you need to, gently tamp it down around the plant, and water a bit more.
5). Place in the sun and keep loving them as they get bigger!
Woo! So many tomatoes!! (And I have more, hah!) This is where sharing comes into play :)