Someone approached and asked me to develop a mobile application for iphone, blackberry, android and windows. My question is do I need to develop using different SDKs for each of the mobile? Secondly, is there a cross-platform tool I can use which code ones and works for all? If not, what is the easiest way for me to code for each of the platform. Please note, I do have programming knowledge and experience in C, C++ and C# and I also worked in Java, so learning is not a problem, but time to get the work done is what I'm looking for. Thank you