Alright Here is step by step guide.
1. Create an account at this site-
Symbian Certificate Application and software online signing - OPDA.CN
2. Apply for certificate providing your IMEI correctly.And Wait for 24 Hrs to get your certificate ready.
3. Sign in and download the two files with extensions .cer and .key
4. You will see a link called signing softs. Click it .
5. Download the app called free signer.
6. Sign it .
{ You Can Sign it on the same site. Just follow the steps
1. Click on my certificate.
2. Click in signing.
3. Upload the downloaded free signer .
4. It will sign it automatically, now download the signed one.
}
7. Install this free signer.
8. Move the two files that you had downloaded earlier.(.cer & .key) into your phones memory card.
9. Run the app .
10. Go to settings and select signing certificate.
11. Browse and select the file which has .cer extension.
12. Select signing key.
13. Browse and select the file which has .key extension.
Thats it u r done.
Now you can run the app and select any app installation file on your phone(mem Card) and sign it without the problem of signing them on internet everytime.
I hope i was able to help you.