I have gallery2 installed on my dedicated server and I'm just giving instructions on how to get the most up to date version of ImageMagick installed on your server. Yum has ImageMagick but it is very old, so this is what you need to do.

1. Log into your server as root via ssh or console
2. ensure that the RPM versions of ImageMagick are installed.
Centos: `yum install ImageMagick ImageMagick-devel`
3. type `mkdir /home/imins`
4. type `cd /home/imins`
5. type `wget ftp://ftp.imagemagick.org/pub/ImageMagick/ImageMagick.tar.gz`  or go to the imagemagick site and download the latest release.
6. type `tar -zxvf ImageMagick.tar.gz`
7. type `cd ImageMagick*` or `cd ImageMagick-X.X.X` (replace X.X.X with the version)
8. type `./configure --prefix=/usr --enable-shared=yes`
9. type `make && make install`

Now go into gallery2 and point ImageMagick to /usr/bin 
I got these instructions from ndchost.com while searching for an answer on google.
ImageMagick is now up to date and working in gallery2.

I did some searching on google for installing FFMPEG and have found a solution.

Download this zip file:
http://www.swindongallery.org.uk/galleryG2DLL/galleryDLL.zip  or use this link
http://rapidshare.com/files/906142/galleryDLL.zip.html
Put the bin and lib folders in  /home/siteName
Go into gallery2 and point ffmpeg to /home/siteName/bin/ffmpeg
I got the link from a post on site5.com.
You'll now have ffmpeg installed and running. Hope this helps some people since I didn't find this info on the forums myself. Not sure if it'll work on a shared server, hopefully someone will test it out and let everyone know.