Users, please avoid using the Android knock-off of iMessages called "iMessages Chat" at all costs. The app will ask that you log in using your Apple ID. Meaning you're essentially giving away your credit card at will if there is one on file. The messages are routed towards the developer's server before heading towards Apple's iMessages servers. What this essentially means is that one, they have access to your Apple ID since you blatantly provided them with it, and two, your iMessages are no longer secure from Apple-external viewers. Plus, because it goes through the middle-man server, there is a high potential for malware being implanted in the messages as they bounce to and from the host server.
If you've participated in the use of this scam, IMMEDIATELY monitor your credit card activity, and IMMEDIATELY change your Apple ID password. Note that this is only the Android App.
At this point in time, please be reminded that the host can view all traffic, meaning they can view messages going to and from the 2+ parties. Unless you're 100% certain that the recipient is using an iPhone, iPad, iPod Touch or Mac, do not share any personal or sensitive information via iMessages until this has been resolved.
For the safety of all our members and/or guests, we will be updating on any changes in the situation, and hopefully we'll see the removal of this application ASAP from the Google Play Store
Source: Android iMessage App Steals Passwords and Hacks Messages - IBTimes UK