vBulletin is most popular forum script. vBulletin is not a free script even after it is most used form software on the web. It is very good and best supported software.
Many vBulletin forum use default template comes with vBulletin. If you want to use different vBulletin skin then there are many free and paid skins available. Skins can easily change your forum look and make it more beautiful. Here are 5 free vBulletin 4 skins.
5 Beautiful vBulletin 4 Skins
1. Bitten Fruit Free
5. Take Five Free