What is exact meaning and usage of 「またこんど」? I know that is like saying "see you later", but it's not very clear to me. Should we use Kanji in this phrase?
While either way is readable, Kanji is usually used for this phrase; a quick google search reveals:
A translation that fits all the usage patterns for また今度 is difficult but the best I can come up with is: "to do something at a later date", with また meaning "later" and 今度 meaning "a later time" or "next time". See the link provided by cypher (Why does 今度【こんど】 mean "next time"?) for a good explanation of 今度.
So, when saying また今度 in the "see you later" context, it's more like saying "another time", though "see you later" would probably be an accurate translation.
#1 A: 『映画を見に行こう？」 (Shall we go see a movie?) B: 「また今度。」 ([Let's do it] Another time.) #2 A: 「今日は楽しかった！じゃね！」 (I had a good time today! See you later!) B: 「また今度！」 (See you later!)
A more literal translation of B in #2 would be something like "Let's do it again sometime!"; either translation would be accurate.