Labib,

At a 10,000 foot level v3.0 was superceded by . v1.0.

TLSv1.0 (RFC 4346) was an upgrade to SSL v3.0 (but they don't interoperate)

This "Cisco.com document" describes the workings of both in some detail:  SSL: Foundation for Web Security

it states this as some basic differences:

...

TLS uses slightly different cryptographic algorithms for such things as the MAC function generation of secret keys. TLS also includes more alert codes.

...

Also See: Wikipedia TLS

As far as which to use, it would depend on if both sides (server/client) support each?  TLS v1.0 or v1.1 is newer.

Most modern Browsers tend to support both.

i.e.

• Firefox 3.5.7 supported both SSL v3.0 and TLS v1.0
• Internet Explorer v6 supported both SSLv2, SSLv3, TLS v1.0
• etc.

Hope that helps.

Steve Ochmanski