Well, if you're ever confronted with a similar problem, there are actually several things you can do. In this article I'll mention only a few of the free services that I've used or know a little bit about.
Dropbox: By far one of the coolest things on the internet right now. The main purpose of dropbox is to allow you to save your files (up to 2 GB of total space, size of individual files don't matter) on the internet so that you can access them wherever you want to. But, since it allows you to save files in the internet, you can use if for back up purposes as well. Finally since it allows you to "share" files and folders with others (with the whole world or with a select group of friends that you can invite) you can also share files that would otherwise make for some very large attachments. Definitely the first thing you should check out.
Windows Live SkyDrive: This free service from Microsoft allows you to store files on their servers so that you can share it with others. It provides 25 GB of space, specifically for this purpose but upload size for each file is limited to 50 MB. Certainly worth checking out, especially for photos, since it also provides a great gallery feature and integrates nicely with other Windows services such an Windows Live Photogallery.
Yousendit: Like some of the other free webhosting services, yousendit allows you to upload your file, and sends that link to your friend so that they can download it via yousendit. While yousendit only stores the file for some days, it might be worth it since no actual sign up is necessary.
Office Live Workspace: While not strictly a file sharing service, office live workspace works great for sharing documents with others, and allows up to 5 GB of storage space. While it does requrie you to have an office live addin for some features, it is great for colloboration. It allows you to allow multiple users to edit a document, add comments and has features like todo lists and so on.
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