You will also find that there are other places in the city, that have their own identity as well, such as Caballito, Boedo, Almagro, Congreso, Colegiales."steveinbsas" said:Regarding San Telmo...yes, a google search will produce significant results.
I am very familiar with the area. For me it's ok for an occasional Saturday afternoon visit (it's much more crowded on Sunday with the street performers and the flea market). There are much better and much safer (albeit more expensive) places to live in BA. San Telmo does have a number of hostels and temporary apartments that appeal to students and those on a more limited budget. I believe is is essential to have advanced language skills to live in San Telmo. Palermo Soho is a lot nicer, with few high rise apartments, but some might find it a bit too trendy. Of course Recoleta is one of the nicest, but relatively more expensive neighborhoods. Its is best to be on the "river" side of Av Santa Fe (away from Av Cordova).