New Guy

You will need some "regular" tools + some bike specific tools

1. Freewheel removal tools specific to the new BMX Freewheel you buy + one for the old Freewheel
   
2. Cone wrenches (probably a 14mm + a 15mm ... there is no standard)
   
3. a GREEN Park-or-other-brand spoke wrench
   
4. Chain tool
   

• I had an OLDer, first-generation Shimano Freewheel for which I didn't have the tool, so I brought the wheel to one of my LBSes ... they didn't have the Freewheel tool to sell OR in their shop (!?!) to remove it with ... so, because I wasn't concerned with salvaging the Freehub, I ended up grinding the smallest cog & Freewheel mechanism off and then using a large pipe wrench to remove the portion which was threaded onto the hub -- Kids, don't try this at home UNLESS you are VERY HANDY.
  

IMO, the most difficult part about setting up a Single Speed bike is choosing the chainring & cog combination ...

• Most frequently, when converting an existing 10-speed to a Single Speed I think that most people will simply use one of the two chainrings which are currently on the crankset -- for example, either a 53t-or-52t chainring OR a 42t-or-39t.
  

If you look at a lot of off-the-peg configurations, the 42t is the most common chainwheel with a 16t cog.

• You can achieve the approximately the same gearing by using an 20t cog with a 52t chainring.
  

Presuming an alloy crankset, if you know which chainring you are NOT using, then remove it. You may need different chainring bolts OR you can use chainring spacers.

• If the bike has an older, steel crankset, then often the inner chainring is bolted to an outer chainwheel ... if you will be using the outer wheel, then remove the inner ring.
  

Decide which cog on the Freewheel is the one you want to use ... then, buy a 3/32" BMX cog with the tooth count that you want.

• You can buy BMX Freewheels from DANSCOMP.COM, eBay, or some (if they cater to BMX riders/bikes) LBSes.
  
• Although they are not the least expensive, ACS Freewheels are probably the best value ... Shimano, next. Avoid Dicta.
  

You will want to center the rear hub & re-dish the rear rim ...

• Beneath the 5-speed Freewheel will be one-or-more spacers ... if there is only one large spacer then you may want to get two new spacers whose total length equals the spacer you remove (presuming there isn't a spacer on the non-driveside -- if so, then figure out what spacer lengths you will need to center the hub between the outer nuts). You may as well repack the bearings with fresh grease ... you can find WHITE LITHIUM in squeeze tubes in automotive supply stores OR the automotive section of WalMart/KMart/etc.
  

• Re-dishing the wheel involves loosening the spokes on the driveside, first, and then tightening the spokes on the non-driveside ... sometimes, new spokes are necessary because the driveside spokes may-or-may-not be too short ... PATIENCE IS THE KEY!
  

Remove the derailleurs (if you haven't already done so).

Place the rear wheel in the frame & shorten the chain, accordingly.

Other than wiping the years of grime from the bike, adding air to the tires, adjusting the saddle height & re-wrapping the handlebars, you will basically be DONE!