Too Many Toys is a great book by David Shannon that most of us parents can relate to any time of the year but the day after Christmas this feeling multiplies!
I am in a guest room in my in-laws' house knee deep in toys, and we have more than we can store or ever possibly play with at home waiting for us. Here is my plan for culling the mess.
During nap time or when your kids are out of the house:
First grab 3 flat sheets or large towels. Make one the keep pile, the next the pass pile and the last the throw away/recycle pile.
The Keep pile is easy - things that your child actively plays with or will grow into. As soon as this pile is full put the toys away. Find places for everything even if it's just a bin, make that toy live in that bin. Trust me this will make finding and playing with toys much easier for everyone.
The Pass pile is one that you put toys that are in good condition but your child has outgrown, just doesn't like or you have doubles of. You can choose to pass these on to friends, charities (women's shelters often need toys!), or you can try local consignment stores who are usually short on toys this time of year. However you do it, get these toys out of your house.
The Ditch pile is for toys that are broken, colored on, and you simply haven't gotten around to get rid of. Or those toys that you don't think are safe for anyone- please don't pass these on to goodwill etc... if they aren't safe for your kids they aren't safe for any. Ditch 'em. Check the bottom of your toys for recycle symbols and pop them in your blue bin if you can.
I wish you luck, if you wish me some... toys aren't always easy to get rid of, some hold awesome memories but really they will play better with less mess and if you are anything like me you will sleep better too!