You can only deduct charitable contributions, such as those made to the ASPCA, from your taxes if you itemize deductions. Itemizing only makes sense if the total of all your deductions adds up to more than the standard deduction. In 2010, the standard deduction for a single person was $5,700, $8,400 for a head of household and $11,400 for a married couple filing jointly.
When you make a donation to a charitable organization, you need to keep a written record to prove the amount of your deduction to the IRS, should you ever be audited. If the ASPCA sends you a thank you note acknowledging your gift, this qualifies if the note lists the amount you donated and is dated. A canceled check or a credit card statement that shows the date of the donation, the amount donated and that is was donated to the ASPCA also qualifies.
If you donate bags of dog food, cat treats, an animal carrier or other items to the ASPCA, you can deduct the value of these items from your taxes. Again, you'll need a receipt from the ASPCA acknowledging your donation. The IRS allows you to determine the value of the donations you made, but the value should be the amount you would reasonably expect to receive from selling the items. If you purchase items such as food or pet toys new and donate them, the receipt from your purchase can be used to establish the value.
If you volunteer to walk dogs, hand out fliers or work at a fundraiser for the ASPCA, the IRS doesn't allow you to deduct the value of your time. However, you can deduct 14 cents per mile for the trip to and from your volunteer job, as well as fees for tolls and parking.