IF the main download link doesn't work use this backup server DSemu.zip
Whats new in this version of NDS emulator?
CPU Core: 40%
ARM: 55%; very damn buggy
Thumb: 20%; broken core
ARM9: 10%, couple of opcodes only
GPU: About 60%
Bitmap modes: 80%
Tile modes: 75%, multiple backgrounds
Sprites: 60%
Rot/Scale: 60%
Mosaic: 75%
Keypad input: Call it 50%
Load roms on DSemu Emulator
the project is not quite dead. Chris Double of New Zealand has put together a set of patches that seem to fix a lot of bugs and add new functionality to DSemu. He's amalgamated them into a new version, 0.4.0; maybe he has skipped a few major version numbers, but I don't mind. I'm going to try to obtain the source, and flick through to see what the salient modifications are; in the meantime, I'll change the Download link to reflect a new version.
Quick Refferance - iDeasS Emulator Key Setup
Keys
Nintendo DS
On PC
D-Up
Up arrow
D-Down
Down arrow
D-Left
Left arrow
D-Right
Right arrow
B
Z
A
X
Start
Enter
Select
Backspace
L
A
R
S
X
Q
Y
W
Stylus
Touchscreen Use the mouse to move and the left button to "touch" the screen.
Page comments : Download nintendo DS emulator emulator iDeaS. Version 10. Free nintendo ds emulators for playing NDS roms that you download from net.
Download DSemu.zip
(latest version) 
