How Google handle 301/302/404/500?

[jimpoo]

I currently redesign my website, should I leave the old pages there or just delete them?

I wrote a .htaccess like this:
---------------------------
ErrorDocument 404 mysite
ErrorDocument 500 mysite
ErrorDocument 301 mysite
ErrorDocument 302 mysite
---------------------------
Do I have any risk on google crawling and indexing?

and if I use the following in .htaccess replace the above, what the risk is again?

---------------------------
ErrorDocument 404 myanothersite
ErrorDocument 500 myanothersite
ErrorDocument 301 myanothersite
ErrorDocument 302 myanothersite
---------------------------

[vitaplease]

you could try a site search on redirects.

jdMorgan seems to be very good at this stuff.