How does Google consider 'redirect from one to another site'?

[viva]

Hello. I have been lurking for awhile but can't find the thread about it. So please help.

I have a new site (www.site2.com) of which I like to promote while I already have one (www.site1.com) doing well with pr4. Now 'www.site1.com' can be found by some not so competitive keywords. But I have to cancel 'www.site1.com' soon. If I promote 'www.site2.com' by using java to redirect visitors from site1 to site2, will it cause any effect on site1 or site2 (i.e. pr)? I already pointed some links from site1 to site2.

Thank you.