Hi,
I've read about some of the working schemes
available for commonwealth countries in the UK Visa website.
Does anyone know of any job opportunities?
Which places/companies are usually hiring?

Any advice or ideas will be greatly appreciated.
Thanks in advance.

In Aus, NZ and Canada, they're hiring Nurses and civil servants. You can only work for one year in australia, though. Most non-commonwealth countries will give you indefinite working visas. If you apply for any job abroad, and get it, you're more likely to be accepted for a visa than going to the country first and looking when you get there. In poor countries, you could look into VSO or English teaching.
The British council run teaching placements around the world.