People can give away money in the form of a gift. In the US gifts are nontaxable below a certain limit. The annual amount exempt from the federal gift tax is $13,000 in 2011. People who file as singles may give a gift up to $13,000 to each individual. If your mother is married, then she may gift up to $26,000 to each individual. The gift tax exclusion is indexed yearly for inflation.
If your mother pays for someone else’s education expenses, the gift will be nontaxable, no matter how large is the amount.