In the wake of current flood calamity, Western Union has waived off money transfer fee to Pakistan starting from 12th August 2010 till 12th September 2010. This waiver is applicable if you are sending money from the United Stated, United Kingdom, United Arab Emirates (UAE), Bahrain, Kuwait and Qatar. Perhaps, a few more countries in the middle east might be eligible but most of the remittance in Pakistan comes from the above mentioned countries.
Additionally, Western Union has committed $100,000 for the flood relief efforts in the country.
 Link to the Press Release