Mobile messaging has become widely used since the release 
of Exchange Server 2003 Service Pack 2 (SP2), which 
provided much needed functionality. SP2 has been able to 
offer remote access users much of the same functionality as 
users working within the network.
Outlook Web Access (OWA) provides remote users access to 
their messaging system via any compliant web browser, 
making mobile messaging universally accessible to any user 
with a browser enabled device.

Configuring the Virtual Directories

When you install the client server access role on the 
Exchange Server, four default virtual directories are 
created to be used by Outlook Web Access. The directories 
are:
/owa - which is used for mailbox access
/Public - used to access public folders
/Exchange - used to access mailboxes and provide backwards 
compatibility
/Exadmin - which provides access for administrative 
settings and properties
These directories are usually sufficient for most 
deployments, but you can create additional virtual 
directories if you require them using the New-
OWAVirtualDirectory command. Note that the forms based auth 
and secure socket layer encryption enabled by default in 
the /owa virtual directory will not apply to the new 
directory and these security services must be enabled 
manually.
Simplifying the OWA URL

Users like simplicity and simplicity reduces the need for 
tech support from the IT helpdesk. The URL that users use 
to access their mailbox via OWA can be simplified using the 
IIS manager. The process simply employs an http redirect 
and you can also set the IIS web page to automatically send 
the user to the secure http URL.
Simply create the html redirect code to 
URL=https://servername/exchange, open the IIS manager and 
program the redirect in the properties of the default web 
site.
Modifying Attachment Handling Settings

A new service introduced in Exchange Server 2007 is Web 
Ready Document Viewing, which allows users accessing the 
messaging servers via OWA to view certain types of common 
documents rendered within the browser.
The document types include Word, PDF, Excel and PowerPoint. 
You can use either the Exchange Management Console or the 
Set-OwaVirtualDirectory command under the manager shell. In 
the console, the settings are located under Web Ready 
Document Viewing settings under the OWA properties in the 
server properties Client Access settings.
Public and private file access can be configured to either 
allow access, block access, or force save the file to the 
client’s device before viewing. All attached files with 
either a default or a known file extension, are by default 
set to one of these three options.
You can also choose one of the options for unkown file 
extensions. Again, you can either use the Exchange 
Management Console or the Set-OwaVirtualDirectory command 
under the manager shell.
In the console you can set the file name extensions in the 
allow, block or force save list under the Direct File 
Access settings page. To modify the list you must select 
Customize direct file access and Direct file access must be 
enabled. There are two sets of settings, one for public 
file access and one for private file access.
Available only in Outlook Web Access Premium client, 
SharePoint and Windows File Share (UNC) integration 
provides read-only access to documents. Administrators can 
configure OWA to allow or block access on individual 
servers, allow or block access from private or public 
computers, create a list of remote servers to be treated as 
internal (only documents on internal host can be accessed 
via OWA), and allow or block access using segmentation.
To set access to individual servers simply add the host 
name to the block or allow list under Remote File Servers 
in the OWA configuration settings. You can also use the Set-
OwaVirtualDirectory command in the manager shell.

By default, Outlook Web Access is enabled for all your 
users after you install Exchange 2003. However, you can 
enable the following features for Outlook Web Access:

•	Set up a logon page.
•	Configure authentication.
•	Configure security options.
•	Configure Outlook Web Access compression.
•	Simplify the Outlook Web Access URL.

When you install Exchange Server 2003 or later, OWA will be installed automatically. You can find it in IIS. For comfort of use you can further download a tool of OWA from Microsoft Site, named OWAAdmin. You can configure OWA by using this tool. You will find this tool in IIS also. Just right click on OWAAdmin and select browse. 

You can access OWA from almost web browsers, mostly used IE6 or higher, Netscape, Firefox and Chrome. You have to provide your Exchange Server name or ip following "/exchange" word. 
i.e. http://myexchange.local/exchange 
or   http://192.168.10.1/exchange