My dad has had his own business since he was 21 - so I have grown up with it really, I am almost his PA sometimes! lol. Having worked in banking too, I have a good knowledge of business banking and accounts, Business plans etc and how it all works, I often had to do presentations on 'Managing your local market' when trying to get the staff to target the right people when selling the banks products - It was very interesting, learning what areas of the town have the most disposable income etc - the information I had access to there was confidential, so I wouldnt have been able to get it had I not worked there.
I think business courses are a really good idea for people who have no / little experience of running a business. A good solid business plan is a really good starting block - as is a cashflow forecast - even before you start looking for premises or setting up. It lets you know what you are really 'in for' in running your own business - and whether it is actually possible for you to make a profit.