With Action replay max u can make cd-r that u can boot with divx, mp3 and even Sega genesis games. Make sure u get the new version of AR Max ... older versions dont makes those divx/mp3/genesis-discs.
Theres some official network software that u can use to connect your pc to your ps2 so u can play divx/mp3 thru your ps2 to your telly (cant remember name sorry).
If u do have Swap Magic (or modchip) u can boot Ps2 media player to play divx/xvid/mp3s.
PSP 1.52 (DG), DS 001, XBOX v1.6B+Cheapmod+120GBHD, SM33, 50004+HDA10+120GBHD, SM32, BP11, 3900X, XBOX v1.6+Softmod, P4_2.666, GBASP, GBA,Celeron_700, DC, PS1, P2_300, TI85, Saturn, GBC, GBP, Megadrive, P75, Amiga 500, MS, 486SX25, Amstrad CPC464, ZX81