reprint from http://www.everythingusb.com/
The good news is that U3 launchpad version 1.4 and higher supports Vista. The bad news is that the update can only be obtained from the U3 drive manufacturers as U3 does not distribute Launchpad updates. If they are slow at adopting the new U3 core, then you will have wait longer or perhaps will shell out for a new drive instead. There are more complications due to Vista compatibility with the mobile apps themselves and the legacy hardware issues that prevent launchpad upgrade for some U3 drives. For example, Sandisk U3 drives with firmware 2.1.5 and 2.2.1 support Vista while firmware 2.1.6, 2.1.7, 2.1.8, 2.2.0 do not. No words about status from Verbatim, Memorex, PQI on their upgrade timeline, but Sandisk will post 1.4 updates in March.
U3 Newbie Guide from same site: