Okay, this is a hard one for the month and may actually require quite a few factors to make work.
1) Computer
2) Dark Night
3) Great Weather
4) Clear skies with bright stars
5) ability to have a slower shutter
6) a fair amount of time to get all the photos.
Do not have photoshop - Do not worry, you can create in layers in Paint Shop or use free software from http://www.startrails.de/ This will allow you to take several photos of less time exposure and then seam them together in a trail pattern.
Okay, so many of you have probably given up reading already and had enough of this, so in order to still work on the concept of trails, slow shutters and standing in the cold in order to get a great shot, feel free to take photos of light trails on the ground or in the sky instead of just focusing on stars if it is too challenging or you have bad weather.
So you only have an iphone, you can get the app Slow Shutter which is really fun to use.
I've been waiting for clear weather for the last few weeks to try this