Added Trial ID number
Added PHP Header

I added this bunch of code as per these instructions:

http://www.paidmembershipspro.com/2012/08/create-a-plugin-for-pmpro-cust
omizations/
Changed the function name

to this:

trial_membership_after_change_membership_level

Because it is called globally in another plugin
Changed Version Number
Added "my"
Added level ID's where I didn't have them
Updated Version Number
Changed line 25 as per these instructions:

http://www.paidmembershipspro.com/forums/topic/trial-period-without-billing-informations/#post-5904
Merge pull request #2 from SketchThis/Function-Name-Change

The plugin now works