Install readpst in ubuntu
Open the terminal and run the following command
sudo apt-get install readpst
Sample command (assuming that you have a dual-core processor, you can run this task in parallel using the -j switch):
readpst -D -j 2 -o ~/Evolution -q -r ~/outlook.pst
You will need to change the paths to where you want to save the files and where you have saved your original .pst file.
After this, start Evolution and use the import feature to import these .mbox files, one-by-one.