M.B.
S., I applaud you for caring heart and wanting to share it with others, I hope you find an avenue that will your Christmas wish to reality. Here a few thoughts to consider for your questions:
1. Check with your local police department or church, other service origanizations they have been doing this for years and have ways of finding those in need in your area.
2. On this topic something for you to consider: Please remember these families are having a hard time and asking for help is an extemely hard thing to do. There are alot of people right now who are having to ask for help that are used to being the ones doing the giving. Please consider their pride and privacy. While I totally understand your wish and the spirt behind your gift sometimes the better lesson to teach and experience is to give without receiving. In other words to give quietly and privately knowing in your heart that what you have done is going to make a difference. That that person or persons is going to know someone out there cared enough to give to them without knowing them.
If you would like your children to experience something more public perhaps these might be some ideas to consider:
Buying toys to take to a drop off for one of the large holiday toy collections that many of the non-profit groups have ie: channel 8 and Santa's Helpers there are many to choose from just the first to mind.
Going to a local mall that has an angel tree and getting angels off the tree buying the gifts and keep doing it till the money is gone.
Going around to local nursing homes and seeing if the have residents that don't have any family local or family at all and asking if it is ok if you bring them something and spend some time with them. They might be able to give you and idea of something they need or enjoy doing ie: someone who crochets or knits might enjoy some pretty new yarn, or one might need a new robe and slippers.
I know many of the food banks and even meals on wheels were starting to take dog and cat food because so many are unable to afford food for their pets. Now I know some may think this is a waste but if that's your only family or friend this is gift that keeps that family together.
I hope this helps to give you some ideas I am sure that you will get many others to help you along.
I know whatever you decide to do it will be with much love!
Merry Christmas!
M. B.