Though Online Mail Services had started allowing larger files but when it comes to GB you just cannot use them. Apart from that there is delay in uploading to mail severs and so on.
You Send it, which Manav has talked when he compared file sending services,is one service which allows you to upload larger has not integrated with Outlook and can be configured to be used as alternative to mail server attachment and upload to You Send it when attachment size exceeds your mail server size.

Send Large files using Outlook
As a summary :
- If File Size > 10MB ( Gmail Limit as an example) , use You Send it to upload file
- else use the default mail server.
On the other hand when somebody receives the mail he can download the files directly from You Send it Servers.
This seem less integration will make sure that you don’t waste time on slow upload or even attachment failures due to file size limit.
One of the biggest advantage of using this plugin is you can send a complete folder if you have bunch of related files to send across. This makes it way easy for you and need not to worry of attaching or even zipping files one by one.
It works with Office 2010 Applications like Word, Excel and Outlook . Download the Plugin