Hi Fahbe....
I use AutoCad at work - I had both in-house training and went on several professionally run courses. Most of all though, I taught myself. I'm not a Cad technician though, I use the package as a design tool (3D ground modelling, road alignment, channel design, earthwork balances etc). You could carry on with your present employment and go to evening classes in AutoCad - my local university for example runs accredited courses. I don't think any particular qualifications are needed, other than some basic computer skills (keyboard and mouse usage), plus say some drafting skills and numeracy. What you could do in the meantime, is purchase a package called TurboCad - a slimmed down version of AutoCad and have a play with that - say draw your house or flat in plan and then draw up sections and elevations to get a feel for the package.
TurboCad V15 costs about �80 new but you might be able to pick up V14 for a fraction of that ! (The professional versions are some �700-�800). You might be able to get hold of a simpler 2D Cad drawing package for a lot less too and if you really enjoy the drafting side of things, then develop into the 3D side of things.
Job prospects - very good I would say - it depends on where you live - but it is a sought after skill in Architects and Engineering Consultancies.