This paper describes BarterRoam: a new novel mobile and wireless roaming settlement model and clearance methodology, based on the concept of sharing and bartering excess capacities for usage inVisiting Wireless Internet Service Provider (WISP) coverage areas with Home WISP. The methodology is not limited to WISPs; it is applicable to virtual WISPs and any Value-Added Services in the mobile and wireless access environments. In the Broadband Public Wireless Local Area Network (PWLAN) environments, every WISP provides its own coverage at various locations or Hotspots. The most desirable option to help WISPs to reduce cost in providing wider coverage area is for the Home and Visiting WISPs to collaborate for customer seamless access via bilateral or multilateral agreement and proxy RADIUS authentication [1]. This is termed a roaming agreement. Due to the large number of WISPs desiring to enter the market, the bilateral or multilateral roaming agreements become complex and unmanageable. The...