does anyone have a tutorial on how to access EDGE thru the $19.99 data plan from t-mobile?

i did have the t-zones plan for $6/month, but i called up t-mobile and they told me that there was a 'glitch' in the system which allowed customers to access EDGE via t-zones via their iphones. that 'glitch' was later fixed and caused customers with iphones to no longer access EDGE with a t-zone add-on, thus me purchasing the $19/mo.

so yeah, basically i just need to know how to change all the settings once again on how to access EDGE with the $20/month plan.

thanks in advance