We had finally created a SMS application, which use standard GPRS USB Wireless modem using Java.
We are ready now to send and receive standard SMS messages and do some mobile marketing and promotions independentrly on SMS agregators.
The modem cost about $250, which is not very cheap, but it only needs USB connection to work. Its hard to find mobile phone, which can be charged using USB only.
The Java library we use for our project is java smslib. (We have tried others too, but this one works ok.)
As soon as smslib will start to support WAP Push, we will do some mobile content promotions too.