Sue Anne Tay writes on the Shanghaiist blog:

For those who are looking to contribute to current aid efforts underway, you can now donate money to the Red Cross Society of China which has formed a disaster relief working group to be dispatched to the earthquake-stricken Wenchuan County in Sichuan.

They have also published an emergency relief hotline, along with bank account information to receive donations to assist their cause:

Account name: Red Cross Society of China
开户单位：中国红十字会总会

For those who want to donate in RMB: you can send money to the RMB account at the Industrial and Commercial Bank of China branch below:
人民币开户行: 中国工商银行 北京分行东四南支行
人民币账号: 0200001009014413252

For those who want to donate in foreign currency, you can send money to the foreign currency account at the CITIC Bank branch below:
外币开户行：中信银行酒仙桥支行
外币账号: 7112111482600000209

Hotline: (8610) 65139999
Online donations: Red Cross Society of China website: www.redcross.org.cn
Click the tab for online donations

UPDATE: The Swift codes for the Red Cross bank accounts listed above are:
for ICBC account (RMB donations): ICBKCNBJBJM
for CITIC account (foreign currency donations): CIBKCNBJ100

For information on more places to donate to earthquake relief efforts, see this page set up by Rebecca MacKinnon and this list from CNReviews.com.