Question: We are arriving into Terminal 2 on the 28th December and want to go to the business lounge in Terminal 1 before getting a flight from Terminal 3 eight hours later.

Answer: 
From [Wikitravel](http://en.wikipedia.org/wiki/Dubai_International_Airport#Passenger_terminals):

> 
> Dubai Airport currently has three passenger terminals. Terminals 1 and
>  3 are directly connected with a common transit area, with airside
>  passengers being able to move freely between the terminals without
>  going through immigration, whilst Terminal 2 is built on the opposite
>  end of the airport. For transiting passengers, a shuttle service runs
>  between the terminals, with a journey time of around 20 minutes from
>  Terminal 2 to Terminal 1, and 30 minutes to Terminal 3.
> 
> 
> 

So it appears there is a means to get between the terminals if you're a transiting passenger, but you have to take the bus, not walk.
I arrived at Terminal 2 at night and had a big surprise: there is no bus that takes you to T1 or T3, only a taxi. So be prepared with at least 50-65 AED to pay to the taxi driver that will get you to T1 or T3 metro station.

Everyone says the transfer is available only if you have a ticket to fly to another destination. I was very disappointed about this.