A challenge for many people is sharing files with friends, particularly files too large for email. Some great free tools are out there to share your files. If you have really big files, you may have to pay some money, but anything under 100 MB can probably be done for free.
I have used YouSendIt.com in the past. It is easy to use. You just have to go to their website and sign up. Files can be sent via the web or with their desktop client you can run on your computer. Anything under 100 MB is free. You can send up to 2 GB with a paid plan. The nice thing about YouSendIt is that you can pay by use. You don't have purchase a full subscription if you just want to use it once or twice.
A colleague recommended Drop.io to me. I just used this twice this week. It is a free service again for files under 100 MB. I think you can pay for more premium services like password access and larger files. Your link is private and won't be caught by search engines. An additional feature is that others with whom you share your drop space can also add files. It becomes a common location of shared storage that can also store comments and you can even email attachments and information. It is reminiscent of a private wiki in many ways. It will also integrate with your Twitter account.
Dropbox a wonderful service that I have been using for a few months now. It allows up to 2 GB of space, and like other services, I think you can pay for more. An additional benefit is that any files you upload and then erase can be retrieved from the trash. You can use it entirely web-based but the real benefit comes in downloading the client on your computer (both Mac and PC work great). It can create a "dropbox" folder in your documents and anything added to your account will automatically sync across computers. I use this to share files between my home computer and school computer regularly. Although convenient for syncing files which can then be run locally on my computer, I find the real power in being able to share folders with others. By sharing a folder, any item placed in that folder is automatically synced to my colleagues' computer. It is a good way to collaborate on projects where multiple files are being used and updated.
These are 3 tools that I have found helpful in sharing files. Perhaps they'll help you as well.