Thank you all for your suggestions
Yes, I understand it looks suspicious to just walk into a forum and try to sell a pony, but I'm not a pony collector myself (though I think they are gorgeous), so that's basically the only reason I came into this forum.
So I think satinslipper's and collector 1's suggestions are the best. Especially if you have a well trusted member in Athens, I could meet up in person with him/her, then he could reasure the buyer the pony is ready to be sent, then the payment could be made and then he/she would ensure that the buyer would receive the pony. Of course the greek member should be a very trusted person so that I could feel safe as well
As for selling it on ebay, I'd rather not, because I'm not familiar with it, plus you need to pay fees and a percentage of your earnings etc etc. And well, I'm suspicious and afraid of internet transactions as well
And one last thing:
I guess this proves I have the pony
Now I'll contact Terrie (satinslipper) and discuss the details and I guess an announcement could be then made that the item can be safely bid for