FastMac today announced the addition of fourth generation iPods to its TruePower line of iPod battery upgrades. “All TruePower batteries utilize patented nanoparticle technology to dramatically extend battery life and feature the industry’s only 2-year warranty.” The company is now accepting preorders for the 4G battery upgrade on its Web site and will be shipping the second week of August. All preorders will receive a free iPod travel charger or a free iPod car charger, at the customer’s preference. Upgrades for Gen 1, 2, and 3 iPods are available now. Pricing starts at US$29.95.