The most convenient way how to convert VMware virtual disk (.vmdk) files would be to mount the image to VirtualBox virtualization software and convert it through some virtual disk manager to one of the other possible formats, such as .ova files (Open Virtual Machine Format). You can do that with the 'create a new virtual machine' function.
Open VMDK file Open OVA fileFree system virtualization platform for Linux operating system developed by Oracle
VMware Workstation is application used to create computer virtual machines in one hosting operating system
A free virtual machine converter by Citrix