This page is intended as a reference for address offsets and formulae for converting codes between different versions of a game (1.0, 1.1 on the same platform, or 1.0, 1.0 on different platforms, etc), so as to provide a centralized list. Without further explanation, I shall add a few. Feel free to contribute. Also, I (LB) have created a small app to carry out these conversions for you (Majestic Porter), which can be found in the Downloads section of GSHI. Hopefully, we'll implement the functions of Majestic Porter in an online app at some point, making them easily available to anyone without a download.
Playstation (GameShark)
Armored Core: Master of Arena
1.0 to 1.1: add 00000060 0000
1.1 to 1.0: subtract 00000060 0000
Diddy Kong Racing
1.0 to 1.1: add 00000040 0000
1.1 to 1.0: subtract 00000040 0000
Driver
1.0 to 1.1: add 00000340 0000
1.1 to 1.0: subtract 00000340 0000
Driver 2
1.0 to Greatest Hits: add 00000540 0000
Greatest Hits to 1.0: subtract 00000540 0000
Metal Gear Solid
1.0 to 1.1: add 00000008 0000
1.1 to 1.0: subtract 00000008 0000
1.1 to Integral: subtract 00002780 0000
Integral to 1.1: add 00002780 0000
1.0 to Integral: subtract 00002778 0000
Integral to 1.0: add 00002778 0000
Mortal Kombat Trilogy
1.0 to 1.1: subtract 00000052 0000
1.1 to 1.0: add 00000052 0000
Persona/Megami Ibunroku Persona
(U) to (J): subtract 000004C0 0000
(J) to (U): add 000004C0 0000
Resident Evil 2
Regular Leon to Regular Claire: subtract 00000238 0000
Regular Claire to Regular Leon: add 00000238 0000
Dual Shock Leon to Dual Shock Claire: subtract 0000008C 0000
Dual Shock Claire to Dual Shock Leon: add 0000008C 0000
Regular Claire to Dual Shock Claire: add 00008080 0000
Dual Shock Claire to Regular Claire: subtract 00008080 0000
Regular Leon to Dual Shock Leon: add 00007ED4 0000
Dual Shock Leon to Regular Leon: subtract 00007ED4 0000
Regular Claire to Dual Shock Leon: add 0000801C 0000
Dual Shock Leon to Regular Claire: subtract 0000801C 0000
Regular Leon to Dual Shock Claire: add 00007E48 0000
Dual Shock Claire to Regular Leon: subtract 00007E48 0000
Tekken 2
1.0 to 1.1: add 000000C4 0000
1.1 to 1.0: subtract 000000C4 0000
Tomb Raider
1.0 to 1.1: add 00000100 0000
1.1 to 1.0: subtract 00000100 0000
Tomb Raider 3
1.0 to 1.1: subtract 000003AC 0000
1.1 to 1.0: add 000003AC 0000
Nintendo 64 (GameShark/Action Replay)
Diddy Kong Racing
1.0 to 1.1: add 00000040 0000
1.1 to 1.0: subtract 00000040 0000
The Legend of Zelda: Ocarina of Time
US GS V1.0 to US GS V1.1: Add 000001C0 0000
US GS V1.0 to US GS V1.2: Add 000006B0 0000
US GS V1.0 to UK AR V1.0: Subtract 00002200 0000
US GS V1.0 to UK AR V1.1: Subtract 00001F80 0000
US GS V1.1 to US GS V1.0: Subtract 000001C0 0000
US GS V1.1 to US GS V1.2: Add 000004F0 0000
US GS V1.1 to UK AR V1.0: Subtract 000023C0 0000
US GS V1.1 to UK AR V1.1: Subtract 00002140 0000
US GS V1.2 to US GS V1.0: Subtract 000006B0 0000
US GS V1.2 to US GS V1.1: Subtract 000004F0 0000
US GS V1.2 to UK AR V1.0: Subtract 000028B0 0000
US GS V1.2 to UK AR V1.1: Subtract 00002630 0000
UK AR v1.0 to US GS V1.0: Add 00002200 0000
UK AR v1.0 to US GS V1.1: Add 000023C0 0000
UK AR v1.0 to US GS V1.2: Add 000028B0 0000
UK AR v1.0 to UK AR V1.1: Add 00000280 0000
UK AR v1.1 to US GS V1.0: Add 00001F80 0000
UK AR v1.1 to US GS V1.1: Add 00002140 0000
UK AR v1.1 to US GS V1.2: Add 00002630 0000
UK AR v1.1 to UK AR V1.0: Subtract 00000280 0000
Nintendo DS
Pokemon Diamond and Pearl
J to U: subtract 00001860 0000
U to J: add 00001860 0000