Currently Verizon is offering unlimited Data Plans for $29.99 and additional $20 for 2GB on 3G Mobile Hotspot. 3G Mobile Hotspot incurs a $35 one-time activation fee.

3G Mobile Hotspot allows your iPhone to act as portable hotspot for up to 5 Wi-Fi enabled computers or other devices — including iPad and iPod touch — enabling them to access the Internet. Please note: When using 3G Mobile Hotspot, all data (including data accessed on the iPhone) will count against your 2GB monthly allowance.iPhone 4, Verizon, Mobile Hotspot