Okay, this is my first code ever, so here goes:
I always want the key items right away (completely impatient, I know), and I couldn't find one for SoulSilver US anywhere, so I took a Japanese one and changed the line B2110DC0 into B2111880 as suggested in earlier posts for converting other codes. It gave me all the key items and I got so excited that I immediately saved the game and posted it here for anyone else who wants to try it. I haven't tried playing anymore yet (I will once I get through here), so I don't know if it will cause a glitch somewhere down the line, but I am keeping my fingers crossed!
ALL KEY ITEMS (L+ R to activate)
94000130 FCFF0000
B2111880 00000000
E00008E8 000000C8
000101B2 000101B3
000101B5 000101BC
000101BD 000101BE
000101BF 000101C2
000101C8 000101D0
000101D1 000101D2
000101D4 000101D5
000101D6 000101D7
000101D8 000101D9
000101DA 000101DB
000101DC 000101DD
000101DE 000101DF
000101E0 000101E1
000101E2 000101E3
000101E4 000101F5
000101F6 000101F7
000101F8 00010214
00010215 00010216
00010217 00010218
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
D2000000 00000000
The second line is the one I changed (it was originally B2110DC0). Hope this works for everyone else, too!!!