Man Utd

The best way to get there is by train. It usually works out a bit cheaper from Leeds, and quite a bit cheaper from York, to buy Advance Single tickets, as compared to a return bought on the day.
If you decide to drive over then I haven't any first hand experience of parking. There is though street parking available within a 10-15 minute walk of the ground, including in the area around the Quadrant (see Pubs below), provided you get there by around one o'clock. Alternatively, you can park at the Lowry Mall at Salford Quays. This costs 3 quid, and the access from/to the M602 is very good. The Lowry Mall is marked on the pub map.   
All the pubs around the ground are basically home fans only. There is though one place near Old Trafford tram stop, the Quadrant, which allegedly gets a mixture of home and away fans. Not only that, there are a few takeaways very nearby, not to mention an offy in case service in the pub is really bad. Another option is Sale town centre, which is only 8 minutes away by tram (from Old Trafford stop).

When travelling over by train our usual pre-match haunt has traditionally been the Waldorf, near Piccadilly. It's a proper pub with a good range of beers, and it does food. Alternatively, some of our lot prefer Sinclairs, which is a Sam Smiths pub over towards Victoria. Being Sams, it has cheap beer. However, they no longer have hand pumps, plus they'll only serve you in plastic glasses.

It goes without saying that there are a few Wetherspoons outlets around. To be avoided is the Manchester and County (the one in Piccadilly Gardens), which can be a bit dodgy. Best is the Waterhouse, which is apparently not your typical Spoons and gets good reviews. Next door to the Waterhouse is the City Arms, which is a belting pub with around eight real ales on at any one time.
Getting to the ground
You can catch a tram from the city centre to the ground. Note that Moseley Street stop is better than Piccadilly gardens because it's a more frequent service. St Peters though is the most convenient stop for the Waterhouse or City Arms. You get off at either Old Trafford or Exchange Quay depending on which service you catch. Basically, follow everyone else for getting off and walking to the ground. A taxi, if you can find one, is a quicker and reasonably cheap way of getting to the ground. However, the best way to get from the city centre to the ground is by train. A special service operates from Piccadilly (platform 14) to 'Manchester United FC', a station at the back of the main stand that's only used on match days. There are 3 or 4 trains before the game, with the last one leaving Piccadilly around half an hour before kick off. There's usually a notice showing train times near the entrance to Piccadilly. Get on the train right at the back and you'll be less than 50 yards from the away turnstiles when you get off. The fare in 2008/9 was 3 quid single or return (so get a return!). The first train back to Piccadilly leaves around 10 minutes after the end of the game. Even if you miss that one you'll still get back much sooner than if you go to Old Trafford for a tram (you could have to queue for up to an hour!). The special buses are a better bet than the tram. But the train's best!

Pub map
City centre pub map
Internet Ground Guide