Only one so far (a good friend), but I'm working on others. Also, my husband has been promised my PRS-505 as soon as I upgrade it. I'm sure I could convert more, though; I blame the lack of availability of e-book readers and their inflated prices here in Croatia.
I saw my first ever e-book reader in a store here in Croatia yesterday! It was a Presagio Libretto, selling for about $200 USD. There was only one left (It was in the electronics section of a grocery store), but it was all locked up so I couldn't play with it. It seems to take every format under the sun.