For SSL to work a valid signed SSL certificate is required. Certificates are a standard way of binding a public key to a name. Public key encryption is a technique that uses a pair of asymmetric keys for encryption and decryption. Each pair of keys consists of a public key and a private key. The public key is made public by distributing it widely. The private key is never distributed; it is always kept secret. Data that is encrypted with the public key can be decrypted only with the private key. Conversely, data encrypted with the private key can be decrypted only with the public key. This asymmetry makes public key cryptography so useful.
You can generate a self-signed certificate and use it for some time until the certificate "signed" by a trusted external authority: VeriSign or Thawte will be ready.
Note: Netscape and Mozilla browsers automatically detect whether a website uses encryption of transmitted data or not (as for Internet Explorer, please encourage your website visitors who use IE to use Internet Explorer 5.0 or later). Thus, if you use a self-signed certificate, your website visitors will be notified that your website uses encryption, but the authority that signed a certificate is not recognized. So if you intend to conduct e-commerce at your website, it is better to obtain an SSL certificate signed by VeriSign or Thawte
To obtain the SSL certificate: