StartupBase - Community of makers & early adopters
Capterra - Capterra helps millions of people find the best business software. With software reviews, ratings, infographics, and the most comprehensive list of the top business software products available, you're sure to find what you need at Capterra.
PitchWall - Browse new startups, and submit your mobile app/games startup's beta page here.
SaaSHub - Find and promote software that will help you grow your business or to be more productive.
Product Hunt - A website that lets users share and discover new products
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.