You can also take Skyliner

http://www.keisei.co.jp/keisei/tetud...ei_us/top.html

It is cheaper (1,920 yen) and fast if you just want to go to Asakusa (or east side of Tokyo) from Narita.

Inside Tokyo, Metro Pass is a good choice especially for the 2-Day Passs.

(1) Tokyo Metro 2-Day Open Ticket (Adult: 980 yen, Child: 490 yen)
(2) Tokyo Metro 1-Day Tourist Open Ticket (Adult: 600 yen, Child: 300 yen)

http://www.tokyometro.jp/e/open_ticket/index.html

For Suica usage, check:

http://www.japanrail.com/JR_icsmartcards.html

Just to share...JR is not very convenient in Kyoto/Osaka. Kyoto has its Kyoto City Pass (i.e. 500 yen per day)

http://www.city.kyoto.jp/koho/eng/access/transport.html

But remember to check the bus sign before you get on. It has to be Kyoto CITY bus but not Kyoto bus...