Andrea,

	Bryan's formulation works well, but I think fixation in fresh (emphasis on
fresh) methanol should be at least 10 minutes.  This is followed by staining
in a 1:10 solution of stock Giemsa:Sorensen's phosphate buffer (pH6.4 -
pH6.8) for 20 minutes.  Rinse in fresh buffer, then two changes 2 minutes
each of buffer.  Better nuclear staining can be achieved by following
fixation with a 50:50 mix of May-Grunwald:Sorensen phosphate buffer.

Diluted Giemsa (and May-Grunwald if used) decay rapidly with time.  They
should be prepared fresh (ideally) before use.  In practice twice daily is
sufficient, but where critical use fresh.

Ingress of atmospheric water into fixative methanol, stock stain solutions
leads ultimately to poor results.

In the US I understand that Wright-Giemsa staining is preferred, again
giving better nuclear and cytoplasmic definition than either stain alone.

Hope this helps

Nigel