C Programming Guide for NIOS - required

Hi,

I am an amateur to NIOSII and have very thin knowledge with this features.

Hereby wish to have yours advise how can i start to develop a sound recording and play back system with NIOSII.

I wish to develop an embedded system that use for sound data analysis with Altera DE2. Microphone is attached to Mic port and the RS-232 is connected to laptop.

Other than that, i also wish to ask is it a better choice of using NIOSII rather than Verilog HDL for same purpose? Would it be hard to write the FFT code with Verilog HDL as i know that NIOSII work with C programming.

Do i need license to implement the NIOSII design on my board?

I do appreciate with more reference or link is provided for me to start the design work.

Many thanks!