Yes,the aim is the same,to vary the camshaft timing.But how it is done is different.
VTEC is simple on and off function.It is rpm triggered.VTEC is a cam changing variable valve timing.It changes to another cam when it engages.The amount of duration and lift (also timing) is determined by the camshaft itself.
VVT (not VVTi) is a cam phasing variable valve timing.It just adjust the opening and closing of the valve (the timing).It is rpm triggered and only varies the timing by fixed amount (like 15deg).
VVTi is also a cam phasing system but constantly varies the timing according to rpm range (say like between 0-15deg).Hence it is not rpm triggered.It is duty cycle controlled.
I-VTEC combines VVT/VVTi and VTEC together.
MIVEC is the same like VTEC,VANOS is the same like VVT/VVTi
For VVTi controller,i suggest Power Enterprise CAMCON CC-101
Just my 2cents,correct i'm wrong :-)