VMware and Citrix have been stepping on each other's toes. A bunch. Will they meet somewhere in the middle, or are they shooting for winner takes all?Citrix continues to push on VMware's enterprise-host foothold with XenServer while VMware ratchets up a new version of its fledgling Virtual Desktop Infrastructure vs. Citrix's established XenApp née presentation server model.

Are they respectively barking up the wrong trees? VMware dominates the virt host environment, and Citrix is the 800-pound gorilla in app and terminal delivery. If you overhear five IT workers talking guested OS at happy hour, it's a good bet they live with ESX. If someone says thin client, the money's on a Citrix mention in the next sentence.

How strong are these two companies pushing to own it all? If eponymous shows are any indicator...

3,300 affiliates attended the Citrix Summit Orlando love-in, where the now-integrated XenSource offerings were formally introduced to channel partners. Citrix is claiming 6,200 channel and alliance partners in total, with 1,600 newbies added in 2007. VMworld had a much stronger 'user' emphasis: close to 11,000 were in attendance, allowing the phrase 'virtualization industry' a bit more credence. VMware is upping the ante with VMworld Europe this month in Cannes. And no, sadly, I will not be attending this year. Despite some very nice offers for lunch. I believe VMware now has north of 9,000 channel partners getting the gospel out worldwide.

The trick for both companies will be pulling off the cross sell. Citrix is working hard to have XenServer as a checklist item with major system vendors; the company is shooting to have its software as an available option for 50% of all shipping servers by year's end. VMware already has 13 server OEMs listed in its Partner Catalog, including Dell, HP, IBM, and Sun.

The channel knows how to sell terminal services, thin clients and app delivery. Or it thinks it does. Desktop virtualization, application virtualization and a variety of new technologies and techniques are at hand to get Word or a med imaging app in front of end users. VMware has to be hoping new and existing customers take a shine to VDI. You can bet the folks at Citrix have been looking over their collective shoulder while putting a shine on XenApp.

And no, I'm not forgetting about VirtualIron. They're sitting on a recent influx of VC money and make great Xen-based products, too. But VirtualIron just doesn't have the same scale of channel presence. Yet. They're working it; the lion's share of new funding is earmarked for 'market expansion.' They have an uphill battle. VirtualIron lists IBM and HP on their tech partner list. Of course, they also list Citrix.

This is a great time to be working the virtualization beat. In three years will we be asking 'hey, remember when we all thought X was gonna take it all,' or 'hey, remember when life was easy and we only had Citrix and VMware to choose from'?VMware and Citrix have been stepping on each other's toes. A bunch. Will they meet somewhere in the middle, or are they shooting for winner takes all?