Honestly, your best bet would be to search through this (and other) forums for topics identical to the one you are starting. There are a lot of them.
Once you have a general understanding of what it takes, and what the various options are, you could then ask more detailed questions. You will find that many devs are happy to assist newcomers, moreso if they've done a little homework first
I want to know about I phone application development. Can you tell me which software will be best for it.
Welcome to the forum.
The dev community is awesome and we will try to help anyone who asks for it.
And on that note...I always ask this as my first question...are you a registered Apple developer? Apple provides basic code examples that will help you understand the building blocks of making an app. As far as the software, the SDK from Apple is all you need really. Get the SDK and get some examples to get going. Other than that see @schplurg answer...search the threads.