Do you want to transfer some big files over the Internet using Gmail?
If the file is not an exe and less than 20 MB, you can send it as an email attachment in Gmail. Else upload the file to Rapidshare or YouSendIt and put the download link in your Gmail message.
That’s a popular approach but you may also want to check the new Gmail OpenBox service from box.net.
Using Gmail OpenBox, you can upload large files to Box.net and send them via Gmail with a simple right-click. Technically, the workflow is the same as sharing with RapidShare but this is more convenient and you have lot of options.
For instance, you may share individual files in your Gmail message or put multiple files in a folder and send a link to that folder. Your recipients will also get to view the contents of the file online using the built-in file viewers of Box.net. And you may unshare files anytime.
To use Gmail OpenBox, create a free account at box.net and then associate the Gmail service. You may use the same approach to share files via desktop email clients like Microsoft Outlook and Thunderbird.
Update: The free account imposes a limit of 10 MB per file but you may put multiple files under one folder in box.net and share the link of that folder via Gmail.