I have to make some assumptions about your question. Namely, that this doesn't have anything to do with Twitter. I know MoPub keeps some of their documentation on Twitter, and I'm hoping that's what you're referring to.
So, if you are just asking "Does MoPub for Android still work in Eclipse projects?", then the answer is "Yes".
I just used the latest and greatest MoPub Android SDK (3.4.0) in a new project in Eclipse, and it works just fine. The sample on GitHub (mopub-sample) also works in Eclipse.
I prefer the MoPub documentation on GitHub over their Twitter docs. In this document, you should follow the steps, and because you're not using Android Studio, skip the steps from Gradle Integration, until you get to Eclipse Integration. They have excellent screenshots and instructions for Eclipse.
Just make sure you finish the document, including Adding the Support Libraries to Your Project, and Adding Google Play Services.
If following this (GitHub) documentation doesn't work for you, please post follow-up questions with more specific details.