How to be a volunteer at a hospital or clinic

Hi,
I'm in Woodbridge, VA. Can anyone give me for tips on how to be a volunteer at a hospital or a pratice. I'm trying to apply for nursing. Sending my kids to preschools so I have about 6hours a week of time without the kids. I'm thinking to volunteer to gain some experience in the field.
Thank you for any input
I found my volunteer positions through the hospital's website, specifically their volunteer application page.