Yup, we did it in 2005. We booked a tour through Flight Centre, I can't remember the name of the local Turkish provider (similar to this tour:
2 Day Anzac Day Tour 2013 - Anzac Day Tours, Anzac Day Dawn Service 2013, Anzac Pilgrimage Tours, Battlefield Anzac Tours, Travel Anzac Gallipoli Tours). I think our tour was a "Sapper" tour, basic two days. We were picked up in Sultanahment in Istanbul early on the 24th, with a bus trip to Cannakkale/Gallipoli area. We stopped once along the way at a kind of roadside diner - some food available for purchase, and toilet facilities. I don't think the bus had a loo in it. Many of the Aussie girls/ladies on the tour buses (a few stopped there at once, huge lines for food & our half-hour stop went by quickly) obviously hadn't done much backpacking in Asia, and were all lining up for the one western loo in the ladies. No lines for the traditional squat toilets, which were being washed out after each use by a cleaner with a bucket.
We had some time around Gallipoli in the afternoon, saw a museum, the Turkish president and his two black hawk helicopters, and went to about 3-4 different spots in the afternoon, including Lone Pine, Chanuk Bair, the beach, the man with the donkey's grave.
We were then taken to a BBQ/Disco for our dinner and evening entertainment. Seemed to very much cater for a backpacker crowd, and a few on our bus didn't appreciate it. It seemed somethin gto do to while away the time until taking us to the dawn service area at around 11pm.
Being the 90th, there were a lot of people there. The roads around Gallipoli were all turned into one-way roads for the day. So, when our bus took us to the Dawn Service site, it had to stop and park after the other 170 buses in front of it. I am *not* exaggerating on that number. Big walk to get to the dawn service site in the dark, and dodging a few drunken backpacker types who had enjoyed the BBQ/Disco entertainment, or perhaps other entertainment, more than we had.
You will need layers and warm clothes for sitting at the site through the night. We were frequently being told to move closer to one another, bunch up, don't lie down, make space as more and more people poured in. We also took sleeping bags to wrap ourselves in. You will then want to strip down to shorts and a t-shirt after the morning service at Lone Pine!!
Lots of waiting for the Dawn service. We were the year that all the Aussie media complained about the "concert" entertainment (BeeGees and Celine Dion videos on the big screens - great fun at 2am) and also about rubbish being left behind. All I can say is, not sure how else to keep a diverse group "entertained" at that time of day appropriately, and there weren't enough rubbish facilities. Also, Turkish loos don't seem to be able to handle very generous western levels of toilet paper usage.
We walked up to the Lone Pine service from the Dawn service site. Our bus would not have gotten through in time. Unless you are able to run, it's very difficult to attend Lone Pine and Chanuk Bair services on the 25th. There is also a Turkish battalion memorial between the two, and there'll be lots of Turks there celebrating their victory.
Got sick of hanging around after the Lone Pine service, so we walked the few kms to our bus to sit in the cool until it slowly snaked its way out of the area and back up to Istanbul. Mr Katie also disrobed behind a bush, heck he would have done it in the middle of the road, to get the long johns off that he needed to be wearing through the night, but were baking him after the Lone Pine service.
We arrived back in Istanbul at around 11pm. A night's accommodation was included in our tour. Very nice hotel, much nicer than where we'd stayed up until the 24th. But it was full of people arriving back from Gallipoli. Not hot water to be had in the shower that night!!
(Please don't regard my comments about lack of hot water, or trekking kms around Gallipoli as whinging. I am very aware these are "first world problems" and absolutely nothing to complain about compared to those who served and lost their lives there. I just want the OP to be aware of some of these logistics)
Mr Katie would like to go back in 2015, but would arrange accommodation in Cannakale, and some kind of private transfer or similar to the Dawn Service site if he does go again. There were aspects of the tour that were cough - sure, the tour guide spoke good English, but didn't know enough about the history of war to be very interesting to us; the BBQ/ Disco on the night of the 24th - but it was a decent way to get there and back when we were unfamiliar with the country.
Hope this helps.