many will do but they may not give you the same colours as the parents. I have had some lovely ones this way.

I agree with Sbg,but you could take off the seed pods now,and dry them..then sow them anytime soon,to have a winter display..or save till spring for next summer...especially if you have a favourite colour..labelled, so you remember which are which..

I agree with the above but because the individual plants tend to be visited by lots of bees etc. as Sgb says you might find a colour you are not expecting from saved seeds. I would always dead head pansies in summer to keep them flowering. Once you start to let seed heads develop the plant thinks it should produce seeds instead of flowers. In the autumn when the flower production starts to slow up give them a feed and cut them back. They will then flower on through the winter. Unless it is very mild you will not need to dead head in winter because the plant senses that it is not warm enough to produce seed. In the early summer repeat the process of cutting back and feeding and start dead heading again. I think if you are growing F1 Hybrids they will not produce viable seed. I'm sure someone will correct me if i have that wrong.

you are right scotsgran most f1 hybrids will not come true from seed, though many will produce seed there are always some sterile forms. Usually find they are the pretty ones too :o(