Formal:
* Mag-usap tayo mamaya. (mag-usap = to talk, mamaya = later) - This is the most literal translation and is appropriate for formal situations.
Informal:
* Usap tayo mamaya. (This is a shortened version of the formal phrase and is more casual.)
* Kita-kits mamaya! (kita-kits = see you later, literally "see each other later") - This is a very common and friendly way to say goodbye.
* Mamaya na lang! (This means "Later!") - This is a very informal way to say goodbye, implying that you will talk or see each other later.
Note: You can also use "ulit" (again) to emphasize that you will talk or see each other again:
* Mag-usap tayo ulit mamaya. (Let's talk again later.)
* Kita-kits ulit mamaya. (See you again later.)
The best choice will depend on your relationship with the person you are talking to.