ONE WEEK!!!!????, one week is really not enough time!, unless it's cheap for you to go there.  

The main reason I'm going is to visit some friends but I want to spend at least one day looking around, I just want to know where to look. I will be near Manila.

go in manila, go to cubau, and have a gr8 time there, that place is sooooo good imo.

june till sept.. those months are rainy days

Here are some MUST see places in Manila:

1. The Mall of Asia, the country's largest shopping mall

2. The US military cemetery with the graves of 17,206 American and Allied soldiers who died in the Philippines and South Pacific during World War II. The thousands of neat white crosses and stars of David stand in rank and file in witness to the epic battles of the war years. The cemetery contains a Memorial -- with maps, photographs and montages depicting the various battles of the South Pacific.
The American Cemetery is the largest American cemetery outside of the United States

3. The Chinese Cemetery (famous for 2-4 bedroom house mauseleum)
4. Intramuros: The city withing the walls 
5. Luneta (Rizal Park)
6. If you are into churches, visit the Manila Cathedral, the Baclaran Church, the Quiapo church

7. Coconut Palace which is a unique structure built of 100% Philippines materials, of which 70% are derived from coconut. This building has had a controversial history. It was built by Imelda Marcos for Pope John Paul's visit in 1981. He was reportedly appalled at the cost and extravagance of the building (when there was such poverty in the Philippines), and he refused to stay there.

8. Chinatown a dirtier bigger and busier version of any Chinatown in the US

9.  Fort Santiago where the national hero, Jose Rizal, was imprisoned and where he wrote his famous poem, "Mi Ultimo Adios". There's a small Rizal museum here now showing his cell and some of his personal effects.

10. Robinson Mall

11. Manila Bay

Have fun and be safe!