The followed steps are very easy to understand and we can easily to remove the .apk signature from the android .apk file
First you need to extract the .apk file ..
Find META-INF folder inside .apk folder and delete it ..
Re-zip it again ..
Next find the your android sdk location
Put your re-modified .apk file into sdk\tools folder...
Create a folder name called like android or other name in any where in your drives
C:\android
Next find .android folder your C:\ drive and you can see avd, androidtool.cfg, ddms.cfg, debug.keystore, default.keyset, repositories.cfg files and all
Take the debug.keystore file Put your debug.keystore file into C:\android folder
Next go to cmd prompt and type followed command
D:\apps\android\2.3\tools: jarsigner –keystore C:\android\debug.keystore –storepass android android –keypass android apkname.apk androiddebugkey.
