Hundreds of people have died, 2 million have been displaced and 14 million lives have been disrupted by exceptionally heavy monsoon rains in Pakistan since July. The U.N. says that even more lives could be lost if aid doesn't arrive soon.
Here's how you can help:
Donate, donate, donate (cash)
The U.S. government and most major relief organizations say that one of the very best ways to help is through cash. Cash donations are easily transferred overseas, don't consume manpower and warehouse space, and can be used by volunteers for the most pressing issues at hand.
For specific aid initiatives, you can look at various organizations that are involved in Pakistan flood relief efforts at InterAction
A few highlights from that list include (and are definitely not limited to):
CARE (Cooperative for American Remittances to Europe)
USA for UNHCR (USA for the UN High Commissioner for Refugees)
UNICEF (U.N. Children's Fund)
If you have specific skills (medicine, engineering, communications, etc.) and want to volunteer your time and energy, go to Center for International Disaster Information.
What is the U.S. government doing?
Go to USAID (United States Agency for International Development) to find out.