Actually, I still recommend being a foster parent; as long as you have some idea of what you are getting into and both parents are on-board it's incredibly rewarding.

If that doesn't apply to you, there's still plenty of things you can do to help out; I ended up on that list from being a foster parent, but I'm sure if you contact whomever is in charge of foster care in your area you can get on the list. Usually whatever local version of child-welfare/social services you have will know what the needs are. Where I am, providing transportation is always a need (e.g. kids to school when they've been moved too far for a bus; kids to and from visits with birth families, &c.)