how to redirect 450 URLs via htaccess

[Catfish]

I have to redirect a long list of app. 450 URLs. Is it ok to do so via htaccess or will this create problems because of file size or number of redirects?
What exactly would the code look like for this ( I have a list of those URLs including rhe respective target URLs)?

Sorry I guess this is a noob question I guess, but I really suck when it comes to this technical stuff. Has to have something to do with age...

[parttimepoker]

That could easily be something that might slow the server down.

Can they be done as a batch? What I mean is, are you changing the same thing about each URL, like making all URLs /category/page instead of just /page?

Here is a good resource on 301s:

Redirection SEO Best Practices | SEOmoz

[Catfish]

No, those are all "individual" URLs like xxx.mydomain.com/my-url.html etc.
So if I did this in the .htaccess, it would have to be like this:
Redirect 301 /oldpage.html http://www.domainname.com/newpage.html - is this correct?

I am still concerned about the effect of a .htacess of xxkb size after putting in 450 lines of redirects. I could try and check site speed before and after though?