At some point in my workflow I want to give a user the option to select multiple users from (preferably) the entire user list or from pooledactors to send a mail to. How do I need to do this?
What you could do is to fill in a property with the list of users who need to receive the email. And then add a "send email" node into your workflow that fires a "send email" action to send email to the list of users.
I have set the cofiguration for email server in custom-email-server.properties. Also selected 'send email' node in workflow. But iam not receiving any mails. Please tell me where is the mistake.
First, configure your mail settings in custom-repository.properties (see here: http://wiki.alfresco.com/wiki/Configuring_Email_for_Alfresco). Test it by inviting yourself to a space and clicking yes to send a notification. If that works, then it CAN work for your workflow as well. If not, you will need to provide more details. Are you using and out of the box workflow? If so, which one? If not, share the relevant part of your jBPM process definition file, content model, and web client configuration for your workflow.
