Trainsignal is the leading Online IT Training provider. Their large course library covers products of the vendors VMware, Microsoft, Citrix, Cisco and CompTIA - and is regularly extended and updated. For those who look to get certified (e.g. as a VMware VCP) they also offer very useful and realistic practice exams.
The training instructors are well-known experts of their domain: E.g. David Davis (@davidmdavis) and Hal Rottenberg (@halr9000) for VMware and Elias Khnaser (@ekhnaser) for Citrix. The course videos are usually divided in multiple short lessons which makes it easy to run through them in a self-paced manner. They can also be downloaded and used with an Offline Player that is available for Windows and Macs (I'd love to have that also for the iPad and Android tablets ;-).
Trainsignal was very generous towards this year's vExperts and offered them a 1-year free access to their training library. I'm currently going through the "VMware Workstation 9 for IT admins" course by David Davis. This course starts with a basic overview of VMware Workstation, how to install it, how to create Virtual Machines, but also includes advanced topics like WSX, managing vSphere and converting machines from various sources. Although I am a Workstation user since years I enjoyed the intuitive (almost entertaining) style of the lessons and learnt a lot. My personal highlight was an almost half-hour walkthrough of creating a complete Windows Active Directory lab setup in VMware Workstation.
The best news is that you can try this and other trainings for free! I love simple pricing models, and Trainsignal's is one of the simplest possible: They offer a flat-rate like subscription model (49 US-$ per month) covering their complete library, and the first three days are for free.
So don't hesitate and start your free trial now!