Yes, I've volunteered at several shelters, and worked primarily with abused and neglected animals. It's extremely rewarding.
It's also how I ended up with my best friend. =^_^=
It's probably a good place to say that I am very pro animal-liberation. Therfore, I am very much against animals being used for any kind of testing, (humans should be brave enough to test their own solutions to things, and if they are not that confident, they shouldn't be at the testing phase to begin with) or being used for clothing and meat. (Except in the case of truly off-the-grid subsistence hunters)