Sam here from OpenSignal. We got this report from a number of users and reached out to Lookout. We got the following email back:
I'm sorry for the confusion. Our latest set of malware detection signatures went out to our users on 12/7/2012. Unfortunately it misidentifies the app "OpenSignalMaps" as well as a few others as the malware. If you've received this warning please ignore it - we are working to resolve the issue.
We also pushed out a quick update which also seems to fix the problem.
In other news we have a huge update to our Android app coming out. If you have Android 4.2 you can already get it, for the rest it should be within a week or two.