Yeah. Two main methods.
1) You get a nice program like auto installer deluxe aka AID and it will come with nice things to click and install whatever dash you like.
2) You FTP manually and replace various files. For the most part it is another homebrew* so you put the folder where it wants to go (typically on the E drive) and replace the jump loader thing in whatever mod you are using. You can mess up booting if you do it wrong so make sure your DVD drive works and you have a copy of Slayer's recovery disc so you can at least launch FTP from that and fix it, alternatively I guess you could make sure you have the keys and a means to access the drive on your PC.
*speaking of other homebrew you can install multiple homebrew dashboards and launch them like other homebrew. I don't know why you would want to go from XBMC but to each their own I guess.