In 2003, there was an anime called Mahou Tsukai ni Taisetsu na Koto. In 2008, there another anime called Mahou Tsukai ni Taisetsu na Koto: Natsu no Sora.
I only saw the 2008 one, so I don't really know much about the 2003 one. They both seem to be about young girls who are learning magic, but is there any actual relation between the two series? For example, are there any subtle hints indicating that the 2008 series takes place X years after the original series? Or are there any characters that appear in both series? Or is the only relation that they have similar stories?
(I had to use the English title for the tags since the Japanese title is too long...)