I lived there for about a year and a half.  The first question is, where in Dalian will you be?  Some people get Dalian mixed up with Kaifaqu and the two are very far apart.

If you are in Dalian, the city center is Zhongshan Guangchang (Zhongshan Square).  If you want an apartment in the area, I would suggest looking at the Houston apartments.  I decent 2 bedroom runs around 2500 per month.

There are tons of nightclubs and bars around this area.  Within 4 blocks of the Houston apartments there are at least 7 huge ones and a dozen or so smaller ones.

The Shangrila hotel is in this area as well.  There is a great, but expensive Italian restaurant right next to it.  Also, across the street is a favorite expat restaurant named "Olive Garden".  Also, to the right of the hotel (as you face the entrance) is a street with many small bars with girls names (Faith, Wendy, Cindy, etc...)  The 'staff' in these bars speak decent english and you will often see other expats in them.  If you are looking for company, that is a good starting place.

Then, no trip to Dalian would be complete without visiting the Alice bar, which is also in the same area.  It is a huge, 3 story nightclub with professional dancers and a host of other 'professionals' that work there.

It is a great place, the summers are awesome, the girls are really tall and there are several micro-breweries in the area worth visiting.

Normal expat bars include Friends & Brooklyn. Just ask any expat you see and they will be able to tell you how to find them.

Have a great time there, Dalian is one of my favorite places in China.