SnowPoint temple can be accessed after the National Dex. There are Lv-50, 60 Pokemon in there, so have your Pokemon up to Lv70 or more before going in. This is how to get to the bottom, where REGIGIGAS is sleeping at the moment. You can wake him up with 3 Pokemon in your party, these are REGICE, REGIROCK, REGISTEEL. It is at lv70 and knows Confuse ray which is annoying! This is a guide to get there.
HM(s) Needed:Rock Smash, Strenth-(Optional)
B1F Go in, there is nothing here but some Weavles and Onixs and Steelix's. Go catch a Steelix if you have not got one. Then go down the stair's.
B2F Easy. Just slide across the ice. Down, right, right, down, right, down the next set of stairs.
B3F A little harder. Smash the first rock you see, then the next you see, the ice is a trick. Slide up, walk left one, down one, and slide across the ice. then down the stairs.
B4F Moderately hard, from the entrance walk next to the rock, (1 away from the wall) Down, left, up, right, up. Down the stairs.
B5F Very-Easy. Unless you want to get the NeverMeltIce. To get it go south from the bolder and push it: 1 up, then run round to the left of it and push it: 2 right, then run on the ice, you will hit the bolder and go right for the item. Then find the stairs and go down.
B6F (Final) Very-Hard. From the entrance step 1 step left and 1 down, slide across the ice. When you hit the floor step 1 down to hit the rock. Then right. Then up. Then on the floor, left, then down, then left, then up. You will see Regigigas. You can awake it by 'Talking' to it with Regirock, Regice, Registeel in your party. It will say 'Zut-Zut' and battle you. Then use an escape rope to get out. Vola, that's Regigigas caught!