TimeEtc - Time Etc offers virtual assistants for entrepreneurs and professionals.
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
WoodBows - WoodBows provides Dedicated Virtual Assistants based in the USA, Philippines, and India at an affordable price.
Ruby Toolbox - Explore and compare open source Ruby libraries
Prialto - Prialto employs expert virtual assistants that can efficiently assist you with challenging tasks.
LibHunt - LibHunt tracks mentions of software libraries on relevant social networks. Based on that data, you can find the most popular projects and their alternatives.