After a few days of creating Circles, I realized that while Google+ was doing a good job of finding people from my GMail contacts that I'd want to connect with, G+ had no idea who my Twitter Followers and Friends were; I searched high and low and couldn't find a tool to find Google+ contacts from my Twitter contacts. Yesterday, I gave up searching and wrote my own tool to do it for you.
You can use Export.ly for free to get a CSV file of your Twitter Friends or Followers, then simply upload them to this tool and you'll get a list of links to peoples' Google Profiles, which very often go to their G+ Profile pages. Follow the instructions carefully.
http://refynr.com/Find_Google_Plus_Accounts_via_Twitter_Contacts.cfm
Keep in mind it's an Alpha product, so there may be bugs, it's a bit slow, and errors are possible. Let me know what you think and how it works for you.
