I can comment on this as I have taught welding on and off for 30 years.I am an Aussie so what applies in my country will be different in yours.
You can go the college route if you have access to one and that is certainly recommended.
Many in my country don't have local college access due to problems signing up -numbers exceed places while other colleges cater for day students only.
A good welding teacher is one one not so much with paper qualifications but one who has a good length experience in the trade /industry and can communicate with people and understand what makes them tick, so to speak .
A good teacher learns as much from his students as they learn from him.
A good teacher watches and learns from his students observing and knowing that everyone has something to offer that others can benefit from.
Yes, it is possible to learn by yourself given you stick to the internet sites of the professional welding companies like Miller, Hobart and Lincoln.
Many of the people writing on the boards mean well, but you can end with some terribly misleading and unsafe info.I have come across instances of self taught people posting incorrect info from other sites for their own websites that were offering this welding information as gospel that in reality was just plain dangerous and stupid.
If you are interested you will learn.Its best to start with with what you want to learn and equip yourself with the most suitable welder to achieve whatever welding task it is that you want to learn.
Remember there is no best welder, rather there is one best suited to the tasks you want it to do and fall within the budget that you have.
If you are going to post to boards, give the readers the the most complete information that you can about what you want to do and achieve.
It enables the person giving the advice to gain a clear idea of what you intend to to do its so much easier for them to give you the details back to you on your specific enquiry.
The thing to look for on board replies is consensus of opinion as most people generally get it fairly right.
If you do get a machine and do some welds ,do not be afraid to to post some pics and ask opinions on your beads.Most blokes are only too happy to help and offer advice. I am quite happy to offer advice should you wish to post .
cheers
Oz