Locator clients for ActiveCampus

You probably want "ActiveCampus Locator + WTD, SH3/ARM", "ActiveCampus Locator XP installer", or "ActiveCampus Locator source" (for Linux, XP, OS/X), depending on your platform.

WTD is from the RAMP group at UCSD and is used to collect network topology data for things like researching peer-to-peer routing. It's also used by the PDA locators for autoupdates so you don't have to keep coming back here and installing new locators. Do Science (capital 'S') a favor and use the WTD bundle, unless you're not comfortable with WTD's anonymous collection of topology data.