You will have to change some of your data types but the basics of what you just posted could be converted to something similar to this given the data types I used may not be accurate.
Dim DateToday As String: DateToday = Format(Date, "yyyy/MM/dd")
Dim Computers As New Collection
Dim disabledList As New Collection
Dim compArray(1 To 1) As String
'Assign data to first item in array
compArray(1) = "asdf"
'Format = Item, Key
Computers.Add "ErrorState", "Computer Name"
'Prints "ErrorState"
Debug.Print Computers("Computer Name")
Collections cannot be sorted so if you need to sort data you will probably want to use an array.
Here is a link to the outlook developer reference. http://msdn.microsoft.com/en-us/library/office/ff866465%28v=office.14%29.aspx
Another great site to help you get started is http://www.cpearson.com/Excel/Topic.aspx
Moving everything over to VBA from VB.Net is not going to be simple since not all the data types are the same and you do not have the .Net framework. If you get stuck just post the code you're stuck converting and you will surely get some help!
Edit:
Sub ArrayExample()
Dim subject As String
Dim TestArray() As String
Dim counter As Long
subject = "Example"
counter = Len(subject)
ReDim TestArray(1 To counter) As String
For counter = 1 To Len(subject)
TestArray(counter) = Right(Left(subject, counter), 1)
Next
End Sub