Okay, so I don't know if I deserve credit for this answer, but this is the answer that worked for me. Go here: for the full run down:
http://withr.me/blog/2013/07/23/configure-shiny-server-under-ubuntu/
Essentially, this site provides the answer which is the following:
sudo apt-get install libcurl4-openssl-dev
sudo apt-get install openjdk-6-jdk
export LD_LIBRARY_PATH=/usr/lib/jvm/java-6-openjdk-amd64/jre/lib/amd64/server
R CMD javareconf # Let R know the configuration of Java;
install.packages(c('RJDBC', 'XLConnect', 'devtools', 'RJSONIO'))
require(devtools)
install_github('rCharts', 'ramnathv')
But if you've not installed shiny server, I would go through the full run down provided at that site. It's essentially a replicate of this site: https://github.com/rstudio/shiny-server/wiki/Ubuntu-step-by-step-install-instructions, but the first site has the above instructions and BAM!!! it works. Now I've got devtools on Ubuntu (something that had been a real pain) and I've been able to download rcharts. For leaflet, checkout:
https://groups.google.com/forum/#!topic/shiny-discuss/V7WUQA7aAiI
Joe Cheng shows how to install that as well as shinyDash. I know Ramnath has leaflet in the rCharts package, but, I'm not able to invoke it with library(leaflet) after installing the rCharts package. So I simply did what Joe said (after all these instructions and typed:
devtools::install_github('leaflet-shiny', 'jcheng5')
devtools::install_github('ShinyDash', 'trestletech')
I don't know if you're needing these, but I do know that if you're recreating some things that Ramnath has done with rCharts, you might find yourself needing these other packages (esp. Leaflet).
I hope this helps, because it certainly helped me!