Yes, there are people who play Arcana Heart. The AH1 thread hasn’t been as active lately since AH2 comes out for PS2 in Japan in a little over a month and pretty much all the AH players are looking forward to importing it.
Master Chibi posted the link to the AH2 thread which is a bit more active at the moment and here’s the link to the AH1 thread:
Also for good info on AH1 check the wiki on www.guardcrush.net but you may want to hurry and save the info since the owner of that site announced recently that he’s taking it down soon.
FYI, if you want to play AH1 with people before AH2 comes out then consider going to Final Round in Atlanta, GA on March 13-15. There’s 20+ pre-regs for it and it might be the last major tournament AH1 will ever be at in the US.