In 2002 I queued for either the first or second day (can't remember, whatever day the sampras/lee match was), got there around 7pm got center court tickets. In 2005 I queued up 4th and qf rounds, both times around 7 or 8pm the night before. I think by the time it came to be my turn the center court tickets were gone, but court 1 had the better matches anyway with federer.
The other thing to be aware of is that there are two queuing lines and depending on which public transp./direction you take to the stadium, you end up in one or the other. It's probably worth it to scout out the length of both lines before joining one.
I've never queued for the first day but most other days. I generally leave the grounds and queue for the next morning straightaway that usually ensures centre court tickets. However you could probably get there by midnight and still get decent tickets it depends.
One guy last year arrived at 5a.m. and got centre court so you never know. Generally i go by midnight onwards rule to ensure Centre Court but it depends how fine you want to cut it.
Jolly good fun though.
16 Grand Slam Titles
The Serena Slam
27 Grand Slam Titles
Hi mate . Queued last year during the first four days and had a blast . My suggestion is to arrive there around 6:00 a.m if you want to make it to the center court on monday and tuesday , a bit earlier from wednesday ( around 5 ) .
Have a look in the OOP the day before as you might see that some or your other favourite players are playing in other courts not the center so you can arrive a bit later .
You´re gonna love it , being in lots of tournaments , but NOTHING BEATS WIMBLEDON .
The smell , the courts, the tradition , you´ll never forget that experience mate .
Plus the queue is pretty funny since it´s like a melting pot .
Have fun mate , cheers !