a script that can help import VMs into VMware ESXi from VirtualBox. tested vbox 4.2.18 and ESXi 5.1.

conv2vmx-ovf.py

#!/usr/bin/env python
#
# usage:
#        conv2vmx-ovf.py some-vm.ovf
#
# ref: http://www.cnblogs.com/eshizhan/p/3332020.html
#

import sys
fn = sys.argv[1]
fp = open(fn).read()
if hasattr(fp,'decode'): 
    fp = fp.decode('utf-8')

fp = fp.replace('<OperatingSystemSection ovf:id="80">', '<OperatingSystemSection ovf:id="101">')

fp = fp.replace('<vssd:VirtualSystemType>virtualbox-2.2', '<vssd:VirtualSystemType>vmx-7')

fp = fp.replace('<rasd:Caption>sataController', '<rasd:Caption>scsiController')
fp = fp.replace('<rasd:Description>SATA Controller', '<rasd:Description>SCSI Controller')
fp = fp.replace('<rasd:ElementName>sataController', '<rasd:ElementName>scsiController')
fp = fp.replace('<rasd:ResourceSubType>AHCI', '<rasd:ResourceSubType>lsilogic')
fp = fp.replace('<rasd:ResourceType>20', '<rasd:ResourceType>6')

end = fp.find('<rasd:Caption>sound')
start = fp.rfind('<Item>', 0, end)
fp = fp[:start] + '<Item ovf:required="false">' + fp[start+len('<Item>'):]

nfp = open('vmx_' + fn, 'wb')
nfp.write(fp.encode('utf8'))
nfp.close()

C:\Users\Nick\Documents>conv2vmx-ovf.py ws1-vm1.ova
Traceback (most recent call last):
  File "C:\Users\Nick\Documents\conv2vmx-ovf.py", line 13, in <module>
    fp = fp.decode('utf-8')
  File "C:\Python26\lib\encodings\utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0x80 in position 13948: inval
id start byte

Ah, terrible UI...

Hy nbolton, How to fix your error you've got above ?