For information on installing the sharepoint 2010 pdf ifiler pleas see Index and Search PDF Files in SharePoint Server 2010 please see Jie Li blog;
Note to allow PDF’s to open directly without having to Save via SharePoint 2010 you can either;
Open Central Admin
Select Manage Web Applications
High-light the portal Applications
Select General Settings
Under Browser file Handling Select Permissive
Alternatively if security policies do not permit the use of permissive run the following powershell;
$webApp = Get-SPWebApplication http://SharePointWebApp
If ($webApp.AllowedInlineDownloadedMimeTypes -notcontains "application/pdf")
{
Write-Host -ForegroundColor White "Adding Pdf MIME Type..."
$webApp.AllowedInlineDownloadedMimeTypes.Add("application/pdf")
$webApp.Update()
Write-Host -ForegroundColor White "Added and saved."
} Else {
Write-Host -ForegroundColor White "Pdf MIME type is already added."
Sample PDF can be found here: http://www.ics.net/Downloads/SharePointAdoptionFrameworkbrochure.pdf