I've only lightly skimmed some of the posts, so forgive me if I've missed something. But some quick thoughts:
If you only want to be able to send/recieve thoughts with a willing person (like a mental radio), then I'd say the price should be low, perhaps -1 refresh. It's similar to an inverted "Supernatural Sense".
If you want to be able to read the thoughts of an unwilling target, then this sounds a bit like an upgrade to Empathy(Reading People). I'd price it at -1 again, but require the above power (or make it a -2 package to get both abilities). This would allow you to make an Empathy roll to learn an Aspect or fact/thought, without the usual Empathy constraint of conversing for a while.
If you want to actually affect/alter the target's thoughts, then I'd use Incite Emotions as a template, but probably change it to a social-based power. Start the pricing at -2 (which includes the 'Range' option from Incite). The 'Lasting' and 'Potent' options could be added as normal to make the attack more powerful than the basic maneuver.