once you have used the love potion don't connect for at least 24 hours then when you connect them again it will work
there is tonnes of cool tama stuff at:
Tamagotchi School
YESTERDAY MY TAMA EVOLVED INTO A MIMITCHI WHEN I GOT A MESSAGE IN THE MAILBOX AND IT TOOK ME TO THIS PLACE BUT I DIDN'T DO ANYTHING AND THEN IT WENT ALL ANGRY AND NOW WHEN I TRY TO GO TO WORK IT JUST SHAKES ITS HEAD. :)