Hey!
Is it really that difficult to get rid of an accent?

The trick just is in the correct position and form of the tongue tip, and root.
One friend of mine had VERY hard (English-like) Ч's and Щ's. But after one ICQ voicechat and a little of theory she got them perfect and even better than some Russians say sometimes. And that usage of the correct tongue decided all the problems with ЧА, ЩА etc., which should sound like ЧЯ, ЩЯ etc.

So, just ask your penpals to tell where's the tongue and you'll be fine.