Yes, "akanie" is widespread in Moscow region. But there are much less people using "akanie" in Petersburg and Novgorod regions though they are situated closer to Finland or Latvia.
This map (http://www.gramota.ru/book/village/map12.html) shows us that "akanie" is mostly widespread in the south part of European Russia (orange colour) and "okanie" in the north part (green colour).
Here is the article in Wikipedia: http://en.wikipedia.org/wiki/Vowel_reduction_in_Russian
Thank you, Mikhail, very valuable resources!
Yes, "okanie" rather than "akanie" is characteristic of the northern part of European Russia, and the border is, actually, not all that far north of Moscow. My major professor at graduate school was from Ivanovo, and his speech was absolutely different from the speech of "korennye moskvichi" - for example, he pronounced the name of his home town with two very strong, "round" "o"-s - "IvanOvO," even though the stress in this word is on the first syllable. He also pronounced the un-stressed "e" and "ya" very differently: "v sEntYAbre pOedu k mOej tyotushke v IvanOvO" (a "moskvich" would say something like, "v sintibre paaaaaedu k maaaaaej tyutshki v Ivanava").
I while ago, I was blessed to listen to a CD, made in Russia and called, "Forgotten Voices" ("Zabytye Golosa"). It had recordings of voices of a number of famous Russian writers and poets, beginning from Leo Tolstoy. Mayakovskiy and Pasternak ("maaaaaaskvichi") did very strong "akanie," while Blok (a "peterburzhets") did not.