I thought you could refight legends in Platinum...? That's what I heard at least...
Yeah, if you kill a one-timer, you can reset it by beating the E4. As for Rotom, wait for the next night.
Did not know that... I've caught all of those tho, including roamers(i used imported master balls...)
@Flipz: is this your first pokemon game? and who are you using in your team at the moment?
Yeah it is, and worse it's only borrowed...I have to give it back on Thursday.

My current team is:
Gyarados ~lvl 28
Grotle (name: Wiggy!) ~lvl 28
Kadabra (name: Kazza) ~lvl 34
Pachirisu ~ lvl 20 (soon to change, I have an EXP share on him and am going to level him up real quick in prep for the 5th Gym boss)
Togetic ~lvl 22 (soon to be removed)
Rotom ~lvl 22
2x Luxio ~lvl 17 (1 male and 1 female, again, I plan to level them up until they evolve, and then pick one to replace Togetic and possibly Gyarados or Wiggy!)
As I mentioned, I'm about to fight the 5th Gym Leader, so I'm stocking up on Electric-type Pokemon.