The practice of yoga is widespread. You will find yoga (the practise of yoga asana or yoga poses) being taught in village halls, gyms, back rooms, yoga schools. There are many styles of yoga (http://bit.ly/OincpZ )and it is very confusing about where to start looking.
I teach Iyengar yoga named after the yoga guru B.K.S.Iyengar who has systematised a scientific practise of yoga. There is great emphasise on care of students so as to avoid injury.
There is no barrier to taking up yoga. The ‘yoga gently’ class we run has students who have started yoga in their ‘sixties’ and ‘seventies’ and who have seen incredible improvements within a short time. Many students have started yoga with limited movement in shoulders, hips, knees etc. In Iyengar yoga we use props that help the student overcome these restrictions and get the maximum benefit.
Of course I will recommend Iyengar teachers. In the UK you must have 8 years personal practise before embarking on a rigourous 2 year teacher training and then ongoing training after you qualify. It is important that you find out your teachers experience and their qualification. Evaluate their class – how safe did you feel with them, where you guided not pushed into the poses? Remember it’s your body.