Okay, having the same question come in from several different clients is a sign that I just need to add the answer here. 

Question: How do I Share files with clients/colleagues/prospects when it is too big or gets blocked from going through email?

Answer: By using one of the many File Sharing Services available on the web.

File Sharing Services are basically renting space to host files specifically- sometimes for backup purposes, sometimes for sharing and collaborating with teams, sometimes to just make a large file available to someone who cannot receive it through email, etc.

You are probably familiar with places that specialize in photo sharing so your friends and family can see your vacation pix, etc. That is just a basic use.

True filesharing sites are more secure. The one I sell through the YNot Shop lets you upload files to a secure location and then email them to your recipients (instead of emailing an attachment, it emails them a link to download the document).  Here’s the link to read more:
Online File Folder (as low as $5/year )

Other file sharing services allow you to set up several users that are allowed to share and view the same space with the option to set some accounts with upload abilities(you) and some with download abilities (your clients). If you’re not a YNot Web client, or prefer one of these other scenarios, here are some other providers off the top of my head:

XDrive (free – $10/month)
GoDaddy ($6/year, go to Email options to find File Folders there)

Now granted, this is not the only way to share files.  Most web hosts will let you set up passworded FTP sites or you could also set up a password protected directory on your web site that holds files and such for downloads.  You then give the password to only those people you want access.  However, I have found this method seems overly complicated for most my clients and the small expense of a third-party file sharing service is worth it for ease of use for both them and their intended file recipients.