How to clean dirty curtains?

[Snog]

I have heavy interlined floor length curtains that could do with a clean.
Dry cleaners seem to charge £8 per square meter which would cost me around £100
per pair.
Can I clean them myself?

Are they visably dirty or could you give them a good hoovering with your upholstery brush on the hoover. If you remove the dust and either give them a good airing outside (watch the sun doesn't fade them) or a good squirt of Zoflora or fabreeze. I am wary of washing curtains as they tend to shrink.

steam them!

Thanks, I will try hoovering them first.
Will using a steam cleaner be a good idea?
What brand of steam cleaner is good for this job?