The Sunset District is divided into different neighborhoods depending on which guide you look at. FriendlyNeighborhoodGuide lists Outer, Central and Inner. Wikipedia adds Parkside. SFGate lists Outer Sunset, Parkside and West Portal.

Hospital:
UCSF Medical Center 707 Parnassus Avenue @ 5th Ave. (415) 502-8914
Urgent Care:
Golden Gate Urgent Care 8-8 M-F 9-4 S-S 199 W. Portal Ave. @ Vicente St 415-821-8798

Libraries:
Google Search
- Parkside Branch Libary (415) 355-5770
1200 Taraval Street, @ 22nd
- Sunset Branch - (415) 355-2808
1305 18th Ave, San Francisco, CA 94122
- West Portal (415) 355-2886
190 Lenox Way, San Francisco, CA 94127
UCSF Library (415) 476-2336
2 reviewsLibrary530 Parnassus Avenue, San Francisco, CA 94143

Transportation:
San Francisco Municipal Transportation Agency (SFMTA, Muni, ) - Buses, Streetcars, Metro light rail, and Cable Cars.
Muni Metro Map | Bikeway Network Map | Bike Map and Walking Guide
The muni metro light light rail trains go thru the Twin Peaks tunnel from West Portal in Sunset to the Castro Station on Market Street.
  Other Maps & Guides | SFMTA

Shopping:
Malls & Shopping Districts:
Stonestown Galleria Mall - 3251 20th Ave near Eucalyptus (415) 564-8848
  Macy's, Nordstrom's, Apple, ...
Lakeshore Plaza Shopping Center - Sloat Boulevard between Everglade Drive and Clearfield Drive.
  Big 5 Sporting Goods, Petco, Radio Shack, UPS, Fed-Ex Office, AAA
West Portal Shopping District - West Portal near Ulloa
Outer Sunset Shopping - Irving St. between 19th and 27th

Grocery:
Safeway - 730 Taraval St, (415) 665-4136
Whole Foods Market - 690 Stanyan St, @ Haight (415) 876-6740
Trader Joe's - 265 Winston Dr, near 19th Ave (CA 1) (415) 665-1835

Hardware:
Great Wall Hardware - 1821 Taraval St, btwn 28th &l 29th (415) 566-1511
Papenhausen Hardware - 32 W Portal Ave near Ulloa (415) 681-6717
Sunset True Value - 3126 Noriega St, (415) 661-0607
9 PM Ace Hardware - 2526 Noriega St, btwn 32nd & 33rd (415) 753-0258

Restaurants:
Yelp
Google Search:
West Portal
Inner Sunset
Parkside
  Copper Kettle Irish Cafe & Bakery - 415 731-8818
  2240 Taraval St. Between 32rd & 33nd

Other:

Radio Shack - 1567 Sloat Boulevard across from 34th Ave. (415) 664-5777
RadioShack - 123 W Portal Ave, @ Vincente (415) 661-2559
Costco - West Portal,
Target - 2675 Geary Blvd @ Masonic (415) 796-5280
Best Buy - 2675 Geary Blvd, near Masonic (415) 409-4960
Staples - 1700 Van Ness Ave, @ Sacramento (415) 771-7030
Apple Store - 3251 20th Ave - Stonestown Galleria (415) 571-2780
Office Depot - Potrero Center - 2300 16th Street near 16th St (415) 252-8280
Dosha Dog - 1314 22nd Ave @ Irving St - (415) 564.5454
Petco - 1591 Sloat Blvd - across from 34th - (415) 665-3700

Links:
Sunset District - FriendlyNeighborhoodGuide
Parkside : San Francisco Neighborhoods - SanFranciscoDays.com