$SMTPServer = "smtp.gmail.com"
$SMTPClient = New-Object Net.Mail.SMTPClient( $SmtpServer, 587 )  
$SMTPClient.EnableSSL = $true
$SMTPClient.Credentials = New-Object System.Net.NetworkCredential( "venkatesh.pnetwork08", "Password" );
$SMTPClient.Send('venkatesh.pnetwork08@gmail.com','manohar.hm@accenture.com','Hi testmail','Test mail for scrptiing')

Error Is:

ERROR: Exception calling "Send" with "4" argument(s): "Failure sending mail."
Script_eventlog_by mailid.ps1 (7): ERROR: At Line: 7 char: 17
ERROR: + $SMTPClient.Send <<<< ('venkatesh.pnetwork08@gmail.com','manohar.hm@accenture.com','Hi testmail','Test mail for scrptiing')
ERROR:     + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
ERROR:     + FullyQualifiedErrorId : DotNetMethodException
ERROR:

 $creds = New-Object System.Net.NetworkCredential( "venkatesh.pnetwork08", "Password" ); 
 $props=@{
      To='venkatesh.pnetwork08@gmail.com',
      From='manohar.hm@accenture.com'
      Subject='Hi testmail'
      Body='Test mail for scrptiing'
}


Send-MailMessage @props -Port 587 -SmtpServer smtp.gmail.com -UseSsl -credentials $creds

Use the CmdLet it is safer.

its Showing Error Like

ERROR: Send-MailMessage : A parameter cannot be found that matches parameter name 'Port'.
Script_eventlog_by mailid.ps1 (10): ERROR: At Line: 10 char: 30
ERROR: + Send-MailMessage @props -Port <<<<  587 -SmtpServer smtp.gmail.com -UseSsl -credentials $creds
ERROR:     + CategoryInfo          : InvalidArgument: (:) [Send-MailMessage], ParameterBindingException
ERROR:     + FullyQualifiedErrorId : NamedParameterNotFound,Microsoft.PowerShell.Commands.SendMailMessage
ERROR:

What version of Windows are you using?

Windows Power Shell 

SAPIEN PowerShell Studio 2012

Windows Power Shell 

SAPIEN PowerShell Studio 2012

What version of Windows? 98,95,xp,2003,7,8...???

Windows Server 2008 R2

Windows Server 2008 R2

You need to upgrade PowerShell to V3.  It has more management functions for WS2008R2 and can more easily manage the server.  It also has updated CmdLets for most things like Send-MailMessage.

http://www.microsoft.com/en-us/download/details.aspx?id=34595

Includes Windows PowerShell 3.0, WMI, WinRM, Management OData IIS Extension, and Server Manager CIM Provider

Here is a better method for setting up the mail client.

http://www.powershellpro.com/powershell-email-alerts/210/

Send-MailMessage : Cannot process argument transformation on parameter 'Credential'. userName
At line:10 char:82
+ ... sl -credential $creds
+                    ~~~~~~
    + CategoryInfo          : InvalidData: (:) [Send-MailMessage], ParameterBindingArgumentTransformationException
    + FullyQualifiedErrorId : ParameterArgumentTransformationError,Microsoft.PowerShell.Commands.SendMailMessage

 $creds = Get-Credential venkatesh.pnetwork08

Powershell's Send-MailMessage -Credential parameter accepts only System.Management.Automation.PSCredential, not System.Net.NetworkCredential. By default, Powershell's interactive Get-Credential command returns a PSCredential object.

To manually create a PSCredential object, follow these instructions (hat tip to bit.ly/RPR4NJ):

$secpasswd = ConvertTo-SecureString "PlainTextPassword" -AsPlainText -Force
$mycreds = New-Object System.Management.Automation.PSCredential ("username", $secpasswd)

Of course, this means your password is now stored and hard-coded in your script, which is not security best-practice.

Sweet ! that did the trick