Fees for SMS also appear to be dropping. For example, Docomo formerly charged ¥5.25 (¥7.25 with delivery confirmation) per SMS, but from 7/13, that price will drop to ¥3.15 (with or without confirmation).
Reportedly, AU (and presumably Okinawa Cellular) will also charge ¥3.15, while Emobile will charge ¥2.1.
Personally, I only use SMS in the rare event that someone's Docomo handset blocks gmail as an anti-spam measure. Even then, I don't like to because the cost per SMS is just absurd.
Assuming one SMS consumes one packet (128 bytes), carriers are charging on order of 10 times what they would otherwise. (Docomo Mova packets are charged at ¥0.315/packet, FOMA packets range from ¥0.21 to ¥0.0525.) A 5 MB download, the average size of an iTunes MP3, at the cheapest data rate would run about ¥2,150 yen. At new and improved SMS rates, ¥129,024 yen. (Using the most expensive old rate, I calculate USD3000!)
This is obviously not a problem limited to Japan.
Check out this excellent interactive graph for packet price comparisons.