static Library in Xcode 4

I am too much of this Static Libary thing in Xcode 4.X

Following are the steps that I usually do..

1)For making a static libary , I open Xcode , new , static libary , and then by adding some classes in the project .. then build phases ->copy headers -> add all headers here one by one,and then i build up the project when run on ios simulator -> static libary does not created ..(red color) when run on ios device - > static library gets created..

2) for using the library.. I make a new Project , then i "add files to project" and also "copy if needed" the following 2 files.. .a file (i.e.static library) folder consisting the headers of library files

Now when I try to import a header file in my project , there is no "suggestion" appear ...but still i write and it does not give an error "header file not found"...

but when I run the project it gives the error like:

ld: warning: ignoring file /Users/Subodh/Library/Developer/Xcode/DerivedData/LibraryImporting_test-cbchzzjdcehzvfgwmzbvifrnrwgk/Build/Products/Debug-iphoneos/libLibraryImporting_test.a, file was built for archive which is not the architecture being linked (i386): /Users/Subodh/Library/Developer/Xcode/DerivedData/LibraryImporting_test-cbchzzjdcehzvfgwmzbvifrnrwgk/Build/Products/Debug-iphoneos/libLibraryImporting_test.a

Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_LibraryImporting_test", referenced from:
      objc-class-ref in AppDelegate.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Plz guide me....point out if get wrong at some step....help plz it will be better if someone mentions all the steps as i have done in making a library and using it in a project...it will be a great help

The key to the issue is this part of the error message:

file was built for archive which is not the architecture being linked (i386)

You have imported the library built for the iPhone Device (ARM) by the look of it, and you are trying to use it in the iPhone Simulator which is i386.

What I would recommend is using an Xcode Workspace where the static library project is one of the projects and the iPhone app is another project. This way Xcode will build the library, as required, for Debug/Release and Device/Simulator.