SharePoint allows a maximum file size of 50MB that can be uploaded into any document library. You can increase the default limit to a maximum file size up to 2,047 megabytes under "Maximum upload size" in the Web Application General Settings page under SharePoint Web Application Management. For detailed steps on viewing the max size & changing it, check this MS KB article - http://support.microsoft.com/kb/925083
If it is larger than 2,047 megabytes, you could probably use some third-party video hosting service or host it on the Cloud - http://aws.amazon.com/ec2/