Step:
1) Create a spreadsheet and paste in your list starting in A1.
2) Insert a row above row 1
3) In B1 put the following text: IN (
4) In B2 put the following formula: =CONCATENATE($B1,"'",$A2,"',")
5) Click B2 and Drag the bottom right corner down until it goes as far as your list
6) Click on the last item in column B and change the formula replacing the last comma with a closing parenthesis similar to the following:
=CONCATENATE($B3,"'",$A4,"')")
7) Copy the item you just changed into your SQL Query and you should end up with something like your original clause:
IN ('item 1','item 2','item 3')

Here's a workaround you can use in Excel...

Step:

1) Create a spreadsheet and paste in your list starting in A1.

2) Insert a row above row 1

3) In B1 put the following text: IN (

4) In B2 put the following formula: =CONCATENATE($B1,"'",$A2,"',")

5) Click B2 and Drag the bottom right corner down until it goes as far as your list

6) Click on the last item in column B and change the formula replacing the last comma with a closing parenthesis similar to the following:

=CONCATENATE($B3,"'",$A4,"')")

7) Copy the item you just changed into your SQL Query and you should end up with something like your original clause:

IN ('item 1','item 2','item 3')

Works great for a long list... :D