I recently had the same situation.  The kitten started using the litter
pan all on their own as soon as they were getting out of the welping
box and moving around the room. (Approximately 4 weeks old.)  If at all
possible you should use something with very low side, say no higher
than 3-inches, to make it easier for the kittens to get into and out of
the box and use plain, clay litter.  The clumping kinds have been
proven to clog up the kittens intestines and lower tracks and can cause
death.

Kittens should not be adopted out before they are 9 weeks old, and
certainly no younger than 6 weeks old, if they are eatting well on
their own and drinking water.  The mother cat can be spayed anytime
after that, but it will be a lot easier for her if you wait the 2 to 3
weeks so she has stopped producing milk.

Hemma

Good idea to check with local groups. There might be vets who from time to
time run very low cost 'spay days'. If not then the group can point you in
the direction for vouchers for low cost spaying. One of our SPCAs do low
cost spay/neuter but have a long waiting list.

You might find a rescue group can help you find homes for the kittens if you
need it.

As has already been said just have a box available once the kittens are
getting around well enough to get into one (around 4 weeks) and mom will
take care of the rest. It is very easy to get the kittens to use the box.

They can wean as early as 4 weeks and as late as 6-7. Mom will pretty much
control that. At some point she's had enough and will 'encourage' them to
eat the food available. You should be feeding mom kitten food at this point
anyway so when she and the kittens are ready they will dig right into mom's
food. If you notice the entire litter is eating kitten food most of the
time, you can start separating mom from the little ones to encourage her
milk to dry up. Just restrict the time she's available to them more and more
each day until they aren't nursing any more and then make her spay
appointment.

Don't know if this group wants jpgs.