Welcome message – Hack to Plugin

I’ve created a little hack that does a nice little welcome message when someone first visits the blog, kinda similar to how comment relish works without the comments part.

You can see more details at: https://www.3wdl.co.uk/2007/06/10/greeting-your-first-time-visitors-and-encouraging-them-to-subscribe/

Is anyone able to turn this into a plugin? Ideally I’d like users to be able to set the text via the WP Admin area, rather than having to change the PHP file.

Any help appreciated..

Thanks
James