From DbMotive Tools:
Oracle Locator Express is a replacement tool for the standard Oracle Home Selector. It sits in the system tray and allows you to easily switch between multiple Oracle Homes with just one click. Oracle Locator Express is also compatible with Oracle Instant client.
What's new in this version:
Version 2.0.1 fixes a bug where the version of the Oracle client was displayed incorrectly for a 11gr2 client