i found this at another forum.
and i quote;
Note that this requires a GBA flashcart. I use my Visoly Flash Advance 128mbit Pro. Most others should work.
First of all, you need DipStar. You can get the latest version here:
http://hp.vector.co.jp/authors/VA018...s/ndshack.html
1. Flash dipstar.ds.gba to your GBA cart with NO loaders or menus. Just that file.
2. Flash dipstar.ds.sav to your GBA cart's sram. I don't know if this is actually necessary, but I did it.
3. You will need to use m3dip.exe to patch any games you want to use with dipstar. Just drag the game onto m3dip.exe in explorer and you will get this:
http://img398.imageshack.us/img398/5749/patchingnu2.th.jpg
It's pretty straightforward. Just hit enter to patch the game, and it will now work with DipStar.
Now, to actually enter codes you will need to either start up your DS without the R4 inserted so you can boot the gba cart in gba mode, or start up a game that has been patched and hold down L while it boots.
Either way, you will come to this:
http://img463.imageshack.us/img463/7092/dipstar1wm5.th.png
Each game "slot" is mapped to a button on the DS. There is no name entry so it is up to you to remember which slot/button has codes for which game. Pressing one of the buttons will take you to the code editor
http://img506.imageshack.us/img506/8613/dipstar2ij9.th.png
You will be putting all the codes you want to use for the game in here.
The controls are simple and laid out on the code editor screen. The basics are:
The arrow keys change your position, A increases by 1, and B decreases by 1. You can hit Start to exit and save, or Select to exit without saving.
Start by putting the master code in, followed by the codes you want.
http://img506.imageshack.us/img506/571/dipstar3zh6.th.png
In this example, code lines 00-01 are the master code. Code line 02 is an Infinite Lives code, and code lines 03-04 are an Infinite Health code.
Once you are done hit start to save the changes, and then turn your DS off and boot up your R4.
Highlight the game you want to play hit A to start it as usual, but then IMMEDIATELY hold down the button that corresponds to the code slot you used for that game, and keep it held down until the game starts up. If you did everything right then your codes should be in effect!
An important note about Wifi play:
DipStar detects games with internet wifi play and will shut down if you try to use it with one. Imaha486 (the author) made an exception for Final Fantasy 3, because all you do with wifi is send letters. Every other nintendo wifi compatible game will fail to run if you try to use DipStar with it. This can be a little frustrating if you want to use codes on single player in a game like Castlevania: Portrait of Ruin. The only way to use codes with wifi games is to use version 3.33 of DipStar, the last version before wifi detection was added. That said, using cheats when playing online makes you a horrible person, and can easily get you banned from Nintendo Wifi... and you will deserve it. You should only use cheats in wifi games in single player offline modes where it won't effect online players. Don't be a douchebag and ruin things for other people.
And lastly, where to find codes? Here are a few places:
http://www.funtopia.nl/cgi-bin/forumscript.pl A small library of DipStar codes
http://forum.gbadev.org/viewtopic.php?t=8662 The DipStar thread at the gbadev forums. People post codes in the thread, but finding the game you are looking for can be tedious, so use the forum search.
http://www.gshi.org Kind of a shameless plug since I'm an admin there.. heh. They have codes for a variety of systems, including a (currently small) DS section. Most codes are in Action replay format and need a simple conversion.
http://kodewerx.net/forum/ People post DS codes in the hacking forum. Some might need conversion.
I hope this helps some people out. If you have any questions or anything needs clarifying feel free to ask. Hopefully I didn't leave anything important out.