PBwiki is a great way to draft and distribute official company policies.  You can begin by creating a policies page and asking folks to contribute, then lock the page once you've settled on the official policies.

[CompanyName] Paid Time Off (PTO) Policy

[Details on vacation policy] 

1st year: 15 days PTO (10 hours / month)

2nd year: 20 days PTO (13.33 hours / month)

3rd year: 23 days PTO (15.33 hours / month)

4+ years: 25 days PTO (16.67 hours / month)

Official company holidays and company retreats, etc. will not count against your PTO.