You can always gift money to your children, but the tax implications will depend on how you do this.

• Spreading gifts throughout your lifetime is a great strategy to help reduce estate taxes. Just be sure to leave yourself enough to live on.
• Gifting up to $14,000 per recipient per year and making direct payments to medical and educational providers on behalf of loved ones are good options for minimizing taxes.
• Any exemption you use for gifting will reduce the amount you can use for the estate tax.

You should consult a financial adviser for guidance based on your specific situation.

This article provides a good overview:

http://www.schwab.com/public/schwab/nn/articles/The-Estate-Tax-and-Lifetime-Gifting