[breakingcontact]

What are some good sights for the M&P Shield? Will sights for the full size work?

Any options to add a light to a Shield?

[jigglyjames29]

Apex sear/FP safety plunger/springs combo
maybe some talon grips
I'm pretty sure the sights are interchangeable.

[MikePaiN]

Some of full size M&P sights hang off the slide a bit but will work.
I'm going to upgrade mine soon with one of these(most likely the XS):

XS Big Dot
http://www.amazon.com/gp/product/B008KUPN7M/ref=ox_sc_act_title_1?ie=UTF8&smid=A1PRQ6XIPVGPBO

or
TrueGlo TFO
http://www.amazon.com/Truglo-Tfo-Handgun-Sight-Set/dp/B0033XZT0M/ref=sr_1_fkmr0_3?s=sporting-goods&ie=UTF8&qid=1354545009&sr=1-3-fkmr0&keywords=%22M%26P+Shield+sights%22

or
Meprolight
http://www.amazon.com/Meprolight-Wesson-Tru-Dot-Compact-Sub-Compact/dp/B0028MCOAM/ref=sr_1_fkmr2_3?s=sporting-goods&ie=UTF8&qid=1354545009&sr=1-3-fkmr2&keywords=%22M%26P+Shield+sights%22

[BILLG]

The option for adding a light is the M&P 9c,M&P 40c or full size versions of the same.They are a much better buy than the shield.

[breakingcontact]

I'd like a compact as well but can't say the Shield was anything other than a GREAT buy.

[340PD]

I put just an Apex Hard Sear in mine and it reduced the trigger pull to just under 6#.

Ameriglo has some Shield sights. Of course they are currently out of stock.
http://www.ameriglo.net/catalog/sights/pistol-sights/smith-wesson/night-sights/complete-sets
Trijicon HD'd very pricy but very nice. M&P's will fit but slight overhang.
http://www.trijicon.com/na_en/products/product2_hdns.php?mid=16