Twitterfall - Twitterfall is an excellent choice if you want something basic, free and without much branding.
Instagram Automatic Posting by Iconosquare - Schedule now. We'll post on Instagram for you later!
Flightly - The must have mobile app for anyone advertising on Twitter.
Grum - Post on Instagram from your computer!
TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
Instaplus - Instaplus is an Instagram automation solution that utomatically likes, comments, follows, and unfollows the target audience.