should do the trick for you. You will need to have some dependancies (such as ffmpeg, mplayer, mencoder, etc.) installed before it will install. Just try the configure script and it will walk you through the installation process. If it comes up and says that some things were missing, exit the installation and install those dependancies by either compiling from source or using your distro's package manager. Then, once you have it installed, cd into the directory containing your avi file and do this.
It will walk you through the process of converting the file. Keep in mind, this will take a long time as it has to decode the video and re-encode it in dvd mpg format. For a 300 MB video I downloaded off of the internet (300MB in avi format) it took 4 hours and the resulting mpg file in dvd format was 3.5 GB. Then, once you have the mpeg file, do this.
dvdauthor -o newdvd/ outputtedfile.mpg
dvdauthor -o newdvd/ -T
Then, open up k3b, go file, new video dvd project, and then drag the files out of the appropriate places in the newdvd directory into k3b (this is really extremely straightforward so i wont bother going into it unless you need help). Then, burn the DVD.
If you have multiple video files, you can skip the 3 commands starting with mkdir newdvd and instead use dvdstyler to make menus and such, which will then make an iso file (warning, don't use dvdstyler to burn the dvd, just make an iso and then use k3b to burn the dvd). (NOTE: you will still need to use tovid-interactive to convert the videos if you are burning multiple avi's to dvd)
That should be everything.
To rip a DVD directly into mpg format, you can use vobcopy+libdvdcss and then use transcode to compress it.