Hello Claudia,
Is there any particular reason why you wish to purchase seeds rather than plants? Plants would be easier than seeds and you could pre-select your varieties. I have not found any catalogue selling scented pelargonium seeds. You could try searching Chiltern Seeds as they list some rare pelargoniums or try a posting on the 'Seed Saving' or "Plant Propagation" forums.
Best wishes
Ron

Hi Claudia
You might find the following search useful"Scented Geraniums or Pelargoniums" James K Sayre. This short article contains some useful information and descriptions of scented Pellies.
Ron

Last year I bought scented mixed geranium seeds, I think 10 seeds in the packet, for $3.95, from Park Seed. Only 2 seeds germinated and one survived outside in a pot all summer. I still have this one growing in the house, but not sure of variety as it hasn't bloomed. I plan to try it outside again this spring, but think buying plants is easier and you can choose your variety. Good luck!

Thanks everyone for responding. Just found a nursery which sells scented pelargonium seeds. Am waiting for the catalog.