Help: process thread control in Web Applications

Currently, I am using vs2005 to develop my personal website. For a lifetime benefit of development, I use this website during development. net2.0 overrides all architectures. One of these architectures is Message Processing (intra-site messages, email messages, and SMS messages ), currently, only when there is a message in the station, a dialog box pops up on the page, showing that there is a new message, while I developed a sending queue for sending the message, though. net2.0 has built-in mail sending functions (such as passwordrecovery). However, if the SMTP server has a problem at the time, it may fail to be sent, therefore, I made a queue to try this failed message multiple times. For short messages, I have developed the send and receive message pairs at the same time, and there is nothing in the send queue. For the receiving queue, we can use mobile phones to remotely control some settings on the website.

In this wayProgramThree E-mail sending threads, short message sending thread, and short message receiving thread are used in the resident thread. However, I found the setting in IIS (application pool) I don't know how to add more threads to my web application process? Please advise.