later on after Manaphi you will be attacked by Palkia on sharkpedo Bluff then capured and taken to the spacal rift. Just go through that doungen twice and battle palkia a 2nt time and he/it will juin your team. Dialga was fun to beat the 2nt time.
[Edited by wifiguy, 7/13/2008 5:20:11 AM]
How long does it take until that happens?