We use MJS Software for that and for Project planning, website building, online directory, etc. It's a PTO specific suite of tools and they're free. Hope that helps.
I use volunteerspot.com to schedule lunch volunteer at my kids school. Each family has to volunteer in the lunch room twice a year. I run a quick hours report to track each families volunteer hours.
Does anyone use a volunteer database/electronic database to keep track of volunteers and hours? We are looking into implementing a program this year and we aren't sure which one to go with.