Yes you can at the Solaceon Ruins. Battle/Catch 99 Unknown and the 100th Pokemon you see will be Celebi.
You can find celebi in the solaceon ruins. First go to the room where you get the four items, read the inscription, and battle 99 unknowns and the 100 battle will be celebi. WARNING: I don't know if this works because I never tried it but my friend did it and showed me the celebi and it came from the solaceon ruins.
in the bottom floor of the solaceon ruins, u have to beat 100 unowns first
You will find Unown in the Solaceon Ruins and the HM Defog.
There are no water stones in the solaceon ruins
you have to fight 130 unown at the solaceon ruins without escaping then the first Pokemon you will fight is celibi lv.30
the solaceon ruins are an optional dungeon for catching the unown. just like the ruins of alph
in pokemon diamond and pearl you get celebi with an action replay or by cheating without using a action replay then you go to the solaceon ruins but before capturing celebi you need to capture all the unown pokemon in the pattern you see in the ruins once you see celebi it will appeared in a room almost to the end celebi will appeared at level.20 hope this works
you get it in the solaceon ruins to the right of solaceon town
In solaceon town there is a section to the right. There is a house and further to the right a cave. That is the ruins.
the item over the entrance to the solaceon ruins (the unown place) is a rare candy
you have to go to the solaceon ruins and fight 130 unown in a row without retreating then the first Pokemon you fight outside will be celibi lv.30