Does anyone know of any easy methods to ignore case of a string literal doing a replace? For instance:

string a = 'one';

string b = 'OneTwoThree';

string c = b.replace(a,'Four');

The above replace would not work due to case sensitivity because string a = 'one' and not 'One'.

Is there some way of ignoring the case on string a?

I have page, Which inturn contains picklists like category when I select one category then the data related to that catogory must be displayed in the table.. Which is all working fine (page/class)but I am getting an error saying ,Too many query rows: 10001.. So can anyone, help me work around this problem...