1. If you're more active on facebook: http://www.facebook.com/twitter/
Adding the selective tweets app on facebook allows you to connect with your twitter account by placing the hashtag #fb at the end of your tweets. This allows you to post only "selective tweets" to facebook rather than every single tweet.
REMEMBER: Don't do both. chose one or the other (I found this out the hard way) or you will have repetitive posts on twitter. Just choose one. Or consider using a 3rd party like Sprout Social or Hootsuite to manage your social media platforms.
HootSuite allows you to connect with and post to multiple platforms and choose which ones to post to! Below you will see my Hootsuite toolbar where I can send a post to twitter, facebook or linkedin. visit http://hootsuite.com/ to get started!
(& feel free to comment any other social media integration tips or software you're using too!)