Siemens will join Salesforce.com's AppExchange roster, which now boasts about 400 plus companies.

OpenScape is a presence-aware applet that gives business users the opportunity to use all of the common communications tools, instant messaging, cell phone, and e-mail, in real time.

The mashup embeds OpenScape within Salesforce's CRM service allowing users to check on availability prior to setting up a conference call, sending an IM, or making a phone call.

"If a customer has a tax question and you are the client manager, you can go on the system and see if your tax specialist is on the phone. If he's available, you can conference the specialist in," said Tien Tzuo, chief strategy officer at Salesforce.

In its initial offering, the mashup is being targeted at the financial services community. Currently Salesforce has 1,200 financial services customers, including large customers such as Sun Trust Bank and Aon with 60,000 financial services professionals using Salesforce, according to Tzuo.