I just deployed the Office Web Applications 2010 Beta. I followed the deployment document Microsoft has provided: http://www.microsoft.com/downloads/details.aspx?familyid=4AC8442D-0974-4902-84FE-1ADE382AB2A1&displaylang=en, but I ran into an error in the Activate the Office Web Apps services and feature by using Windows PowerShell chapter.

This is what the document says in the Create the service applications and the service application proxies paragraph:

After the service instances have been started, the service applications and the service application proxies which connect the Web front-ends to the service applications must be created. Create the service applications and the service application proxies by running the following script:

$appPool = Get-SPIisWebServiceApplicationPool –Name “SharePoint Web Services Default”
New-SPWordViewingServiceApplication –Name “WdView” –AppPool $appPool |
New-SPWordViewingServiceApplicationProxy –Name “WdProxy”
New-SPPowerPointServiceApplication –Name “PPT” –AppPool $appPool |
New-SPPowerPointServiceApplicationProxy –Name “PPTProxy”
New-SPExcelServiceApplication –Name “Excel”
-SPIisWebApplicationPool $appPool |

There are three errors in this script:

1. The -Name parameter is invalid for the Get-SPIisWebServiceApplicationPool command. This should be -Identity.
2. The -AppPool parameter is invalid for the New-SPWordViewingServiceApplication, New-SPPowerPointServiceApplication and New-SPExcelServiceApplication commands. This should be –ApplicationPool.
3. The New-SPExcelServiceApplication is missing a command after the pipe (|).

I skipped the New-SPExcelServiceApplication command, cause my Excel Services Application Service was already created during the Farm Configuration Wizard. So the correct script is:

$appPoolName = "SharePoint Web Services Default"
New-SPWordViewingServiceApplication –Name "WdView" -ApplicationPool $appPoolName | New-SPWordViewingServiceApplicationProxy –Name "WdProxy"
New-SPPowerPointServiceApplication –Name "PPT" -ApplicationPool $appPoolName | New-SPPowerPointServiceApplicationProxy –Name "PPTProxy"
New-SPExcelServiceApplication –Name "Excel" -SPIisWebServiceApplicationPool $appPoolName

If you are looking for a single complete script that handles it all -- here you go

$machinesToActivate = @( gc env:computername )

$serviceInstanceNames = @("Word Viewing Service", "PowerPoint Service", "Excel Calculation Services")
foreach ($machine in $machinesToActivate) {
	foreach ($serviceInstance in $serviceInstanceNames) {
		$serviceID = $(Get-SPServiceInstance | where {$_.TypeName -match $serviceInstance} | where {$_.Server -match "SPServer Name="+$machine}).ID
		Start-SPServiceInstance -Identity $serviceID 
	} 
} 

$appPoolName = "SharePoint Web Services Default"
New-SPWordViewingServiceApplication –Name "WdView" -ApplicationPool $appPoolName | New-SPWordViewingServiceApplicationProxy –Name "WdProxy"
New-SPPowerPointServiceApplication –Name "PPT" -ApplicationPool $appPoolName | New-SPPowerPointServiceApplicationProxy –Name "PPTProxy"
New-SPExcelServiceApplication –Name "Excel" -SPIisWebServiceApplicationPool $appPoolName

$webAppsFeatureId = $(Get-SPFeature -limit all | where {$_.displayname -eq "OfficeWebApps"}).Id
Get-SPSite –limit ALL |foreach { Enable-SPFeature $webAppsFeatureId –url $_.URL } 

And for a bonus if you want to enable the new Developer Dashboard in SharePoint 2010, here is the powershell script to do it

$svc=[Microsoft.SharePoint.Administration.SPWebService]::ContentService

$ddsetting=$svc.DeveloperDashboardSettings

$ddsetting.DisplayLevel=[Microsoft.SharePoint.Administration.SPDeveloperDashboardLevel]::OnDemand

$ddsetting.Update()

And here is the STSADM command
stsadm -o setproperty -pn developer-dashboard -pv OnDemand

Some additional information can be found here