It is quite troublesome to click ILDASM and then search for the assembly whose IL code you want to see.
as you right click .dll or .exe files you get View In ILDASM.exe and eaisly view IL code.
Introduction
This article guides you to little Registry Tweak through which you can open .exe or .dll (Ofcourse .NET Assemblies only!) files in ILDASM just by right clicking on .dll or .exe files.
**BEWARE! If you edit wrong values, then your .dll or .exe files setting may get corrupt**
I am explaining everything from scratch....
STEP 1 :
Go to Run

STEP 2:
Expand HKEY_CLASSES_ROOT

STEP 3:
Type dllfiles or goto HKEY_CLASSES_ROOT\dllfile

STEP 4:
Add New Key by clicking right click on dllfile key
and name that key Shell

STEP 5:
Then Right click the added key Shell and Add new key to it and name it "View In ILDASM".
STEP 6:
Now right click last added key "View in ILDASM" and add new sub key to it and name it "Command"
.

STEP 7:
Now Add Command Key Default value as path to ILDASM.exe with parameter "%1" which sends the .dll
full path to ILDASM when you click "View In ILDASM" option in right click.

Now just right click on your .dll file and open it in ILDASM.

The same step is applied to exefiles also when you want to add right click option for .exe files.
Well this is all, right click and Enjoy.... :)